diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index df9a70ceb..0880cbf95 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -190,8 +190,11 @@ jobs:
           - name: flake8
             tox: flake8
             # continue_on_error: true
+          - name: isort
+            tox: isort_CI
+            # continue_on_error: true
           - name: black
-            tox: black
+            tox: black_CI
             # continue_on_error: true
           - name: Docs
             tox: docs
diff --git a/examples/client_async.py b/examples/client_async.py
index bb0d3164b..c9c368fb7 100755
--- a/examples/client_async.py
+++ b/examples/client_async.py
@@ -20,9 +20,9 @@
 The corresponding server must be started before e.g. as:
     python3 server_sync.py
 """
-import os
 import asyncio
 import logging
+import os
 
 # --------------------------------------------------------------------------- #
 # import the various client implementations
diff --git a/examples/client_async_basic_calls.py b/examples/client_async_basic_calls.py
index 6aa9d2fc6..846ecd404 100755
--- a/examples/client_async_basic_calls.py
+++ b/examples/client_async_basic_calls.py
@@ -9,8 +9,8 @@
 import asyncio
 import logging
 
-from examples.helper import get_commandline
 from examples.client_async import run_async_client, setup_async_client
+from examples.helper import get_commandline
 
 
 _logger = logging.getLogger()
diff --git a/examples/client_async_extended_calls.py b/examples/client_async_extended_calls.py
index cd263c06d..4a7ac69d0 100755
--- a/examples/client_async_extended_calls.py
+++ b/examples/client_async_extended_calls.py
@@ -25,9 +25,8 @@
 import asyncio
 import logging
 
-from examples.helper import get_commandline
 from examples.client_async import run_async_client, setup_async_client
-
+from examples.helper import get_commandline
 from pymodbus.diag_message import (
     ChangeAsciiInputDelimiterRequest,
     ClearCountersRequest,
@@ -54,6 +53,7 @@
     ReportSlaveIdRequest,
 )
 
+
 _logger = logging.getLogger()
 
 UNIT = 0x01
@@ -168,6 +168,7 @@ async def run_async_ext_calls(client):
     await _execute_information_requests(client)
     await _execute_diagnostic_requests(client)
 
+
 # --------------------------------------------------------------------------- #
 # Extra code, to allow commandline parameters instead of changing the code
 # --------------------------------------------------------------------------- #
diff --git a/examples/client_payload.py b/examples/client_payload.py
index 473efd422..c790ee770 100755
--- a/examples/client_payload.py
+++ b/examples/client_payload.py
@@ -7,8 +7,8 @@
 
 Works out of the box together with payload_server.py
 """
-from collections import OrderedDict
 import logging
+from collections import OrderedDict
 
 from pymodbus.client import ModbusTcpClient as ModbusClient
 from pymodbus.constants import Endian
diff --git a/examples/client_sync.py b/examples/client_sync.py
index 321c7e9b8..cd9f8999f 100755
--- a/examples/client_sync.py
+++ b/examples/client_sync.py
@@ -20,8 +20,8 @@
 The corresponding server must be started before e.g. as:
     python3 server_sync.py
 """
-import os
 import logging
+import os
 
 # --------------------------------------------------------------------------- #
 # import the various client implementations
diff --git a/examples/client_sync_basic_calls.py b/examples/client_sync_basic_calls.py
index 509aedc66..d5ae1bef0 100755
--- a/examples/client_sync_basic_calls.py
+++ b/examples/client_sync_basic_calls.py
@@ -8,8 +8,8 @@
 """
 import logging
 
-from examples.helper import get_commandline
 from examples.client_sync import run_sync_client, setup_sync_client
+from examples.helper import get_commandline
 
 
 _logger = logging.getLogger()
diff --git a/examples/client_sync_extended_calls.py b/examples/client_sync_extended_calls.py
index 7a6d92d84..fb80a1905 100755
--- a/examples/client_sync_extended_calls.py
+++ b/examples/client_sync_extended_calls.py
@@ -24,9 +24,8 @@
 """
 import logging
 
-from examples.helper import get_commandline
 from examples.client_sync import run_sync_client, setup_sync_client
-
+from examples.helper import get_commandline
 from pymodbus.diag_message import (
     ChangeAsciiInputDelimiterRequest,
     ClearCountersRequest,
diff --git a/examples/common/custom_synchronous_server.py b/examples/common/custom_synchronous_server.py
index 8e72e63ed..b2d1366de 100755
--- a/examples/common/custom_synchronous_server.py
+++ b/examples/common/custom_synchronous_server.py
@@ -57,10 +57,6 @@ def decode(self, data):
 """
 import logging
 
-from .custom_message import (  # pylint: disable=relative-beyond-top-level
-    CustomModbusRequest,
-)
-
 from pymodbus.datastore import (
     ModbusSequentialDataBlock,
     ModbusServerContext,
@@ -70,6 +66,10 @@ def decode(self, data):
 from pymodbus.server import StartTcpServer
 from pymodbus.version import version
 
+from .custom_message import (  # pylint: disable=relative-beyond-top-level
+    CustomModbusRequest,
+)
+
 
 # --------------------------------------------------------------------------- #
 # configure the service logging
diff --git a/examples/common/performance.py b/examples/common/performance.py
index 3349aaab2..d4a36e2a2 100755
--- a/examples/common/performance.py
+++ b/examples/common/performance.py
@@ -5,21 +5,23 @@
 The following is an quick performance check of the synchronous
 modbus client.
 """
-from concurrent.futures import ThreadPoolExecutor as eWorker, as_completed
-
 # --------------------------------------------------------------------------- #
 # import the necessary modules
 # --------------------------------------------------------------------------- #
 import logging
 import os
-from threading import Lock, Thread as tWorker
+from concurrent.futures import ThreadPoolExecutor as eWorker
+from concurrent.futures import as_completed
+from threading import Lock
+from threading import Thread as tWorker
 from time import time
 
 from pymodbus.client import ModbusTcpClient
 
 
 try:
-    from multiprocessing import Process as mWorker, log_to_stderr
+    from multiprocessing import Process as mWorker
+    from multiprocessing import log_to_stderr
 except ImportError:
     log_to_stderr = logging.getLogger
 
diff --git a/examples/contrib/concurrent_client.py b/examples/contrib/concurrent_client.py
index 26bbb197c..3cacf3c36 100755
--- a/examples/contrib/concurrent_client.py
+++ b/examples/contrib/concurrent_client.py
@@ -6,8 +6,6 @@
 a high level of concurrency by using worker threads/processes to handle
 writing/reading from one or more client handles at once.
 """
-from collections import namedtuple
-from concurrent.futures import Future
 import itertools
 
 # -------------------------------------------------------------------------- #
@@ -15,13 +13,13 @@
 # -------------------------------------------------------------------------- #
 import logging
 import multiprocessing
-from multiprocessing import (
-    Event as mEvent,
-    Process as mProcess,
-    Queue as mQueue,
-)
-from queue import Queue as qQueue
 import threading
+from collections import namedtuple
+from concurrent.futures import Future
+from multiprocessing import Event as mEvent
+from multiprocessing import Process as mProcess
+from multiprocessing import Queue as mQueue
+from queue import Queue as qQueue
 from threading import Event, Thread
 
 # -------------------------------------------------------------------------- #
diff --git a/examples/contrib/message_generator.py b/examples/contrib/message_generator.py
index eea3d8a22..c27c425a0 100755
--- a/examples/contrib/message_generator.py
+++ b/examples/contrib/message_generator.py
@@ -14,6 +14,7 @@
 import logging
 from optparse import OptionParser  # pylint: disable=deprecated-module
 
+import pymodbus.diag_message as modbus_diag
 from pymodbus.bit_read_message import (
     ReadCoilsRequest,
     ReadCoilsResponse,
@@ -26,7 +27,6 @@
     WriteSingleCoilRequest,
     WriteSingleCoilResponse,
 )
-import pymodbus.diag_message as modbus_diag
 from pymodbus.file_message import (
     ReadFifoQueueRequest,
     ReadFifoQueueResponse,
diff --git a/examples/contrib/message_parser.py b/examples/contrib/message_parser.py
index 761bf71df..a076ec3d5 100755
--- a/examples/contrib/message_parser.py
+++ b/examples/contrib/message_parser.py
@@ -17,8 +17,8 @@
 import codecs as c
 import collections
 import logging
-from optparse import OptionParser  # pylint: disable=deprecated-module
 import textwrap
+from optparse import OptionParser  # pylint: disable=deprecated-module
 
 from pymodbus.factory import ClientDecoder, ServerDecoder
 from pymodbus.transaction import (
diff --git a/examples/contrib/modbus_mapper.py b/examples/contrib/modbus_mapper.py
index c69da8d9f..30aa60f92 100644
--- a/examples/contrib/modbus_mapper.py
+++ b/examples/contrib/modbus_mapper.py
@@ -124,16 +124,14 @@
     StartTcpServer(context=context, identity=identity, address=("localhost", 5020))
 
 """
-from collections import defaultdict
 import csv
-from io import StringIO
 import json
+from collections import defaultdict
+from io import StringIO
 from tokenize import generate_tokens
 
-from pymodbus.datastore import (
-    ModbusSlaveContext,
-    ModbusSparseDataBlock,
-)
+from pymodbus.datastore import ModbusSlaveContext, ModbusSparseDataBlock
+
 
 # --------------------------------------------------------------------------- #
 # raw mapping input parsers
diff --git a/examples/contrib/modbus_simulator.py b/examples/contrib/modbus_simulator.py
index 96a3b6efa..f7310badb 100644
--- a/examples/contrib/modbus_simulator.py
+++ b/examples/contrib/modbus_simulator.py
@@ -5,8 +5,8 @@
 with read/write data as well as user configurable base data
 """
 import logging
-from optparse import OptionParser  # pylint: disable=deprecated-module
 import pickle  # nosec
+from optparse import OptionParser  # pylint: disable=deprecated-module
 
 from pymodbus.datastore import ModbusServerContext, ModbusSlaveContext
 from pymodbus.server import StartTcpServer
diff --git a/examples/contrib/thread_safe_datastore.py b/examples/contrib/thread_safe_datastore.py
index 8d9d4c8dc..cb085fb7e 100644
--- a/examples/contrib/thread_safe_datastore.py
+++ b/examples/contrib/thread_safe_datastore.py
@@ -1,7 +1,7 @@
 # pylint: disable=missing-type-doc
 """Thread safe datastore."""
-from contextlib import contextmanager
 import threading
+from contextlib import contextmanager
 
 from pymodbus.datastore.store import BaseModbusDataBlock
 
diff --git a/examples/contrib/tornado_twisted/modbus_scraper.py b/examples/contrib/tornado_twisted/modbus_scraper.py
index 0ddbe6a78..a226a4dc1 100755
--- a/examples/contrib/tornado_twisted/modbus_scraper.py
+++ b/examples/contrib/tornado_twisted/modbus_scraper.py
@@ -5,10 +5,13 @@
 them as a collection of sequential data blocks.
 """
 import logging
-from optparse import OptionParser
 import pickle  # nosec
+from optparse import OptionParser
 
-from twisted.internet import reactor, serialport  # pylint: disable=import-error
+from twisted.internet import (  # pylint: disable=import-error
+    reactor,
+    serialport,
+)
 from twisted.internet.protocol import (
     ClientFactory,  # pylint: disable=import-error
 )
diff --git a/examples/serial_forwarder.py b/examples/serial_forwarder.py
index 99782b3ab..7df3c8f8c 100644
--- a/examples/serial_forwarder.py
+++ b/examples/serial_forwarder.py
@@ -4,14 +4,15 @@
 python3 serial_forwarder.py --log DEBUG --port "/dev/ttyUSB0" --baudrate 9600 --server_ip "192.168.1.27" --server_port 5020 --slaves 1 2 3
 """
 import argparse
+import asyncio
 import logging
 import signal
-import asyncio
 
-from pymodbus.server.async_io import ModbusTcpServer
 from pymodbus.client import ModbusSerialClient
 from pymodbus.datastore import ModbusServerContext
 from pymodbus.datastore.remote import RemoteSlaveContext
+from pymodbus.server.async_io import ModbusTcpServer
+
 
 FORMAT = "%(asctime)-15s %(levelname)-8s %(module)-15s:%(lineno)-8s %(message)s"
 logging.basicConfig(format=FORMAT)
@@ -24,7 +25,7 @@ def raise_graceful_exit(*args):  # pylint: disable=unused-argument
     raise SystemExit
 
 
-class SerialForwarderTCPServer():
+class SerialForwarderTCPServer:
     """SerialRTU2TCP Forwarder Server"""
 
     def __init__(self):
@@ -34,17 +35,19 @@ def __init__(self):
     async def run(self):
         """Run the server"""
         port, baudrate, server_port, server_ip, slaves = get_commandline()
-        client = ModbusSerialClient(method='rtu', port=port, baudrate=baudrate)
-        message = f'RTU bus on {port} - baudrate {baudrate}'
+        client = ModbusSerialClient(method="rtu", port=port, baudrate=baudrate)
+        message = f"RTU bus on {port} - baudrate {baudrate}"
         _logger.info(message)
         store = {}
         for i in slaves:
             store[i] = RemoteSlaveContext(client, unit=i)
         context = ModbusServerContext(slaves=store, single=False)
-        self.server = ModbusTcpServer(context, address=(server_ip, server_port), allow_reuse_address=True)
-        message = f'serving on {server_ip} port {server_port}'
+        self.server = ModbusTcpServer(
+            context, address=(server_ip, server_port), allow_reuse_address=True
+        )
+        message = f"serving on {server_ip} port {server_port}"
         _logger.info(message)
-        message = f'listening to slaves {context.slaves()}'
+        message = f"listening to slaves {context.slaves()}"
         _logger.info(message)
         await self.server.serve_forever()
 
@@ -61,16 +64,22 @@ def get_commandline():
 
     parser = argparse.ArgumentParser(description="Command line options")
     parser.add_argument("--log", help=",".join(logchoices), default="info", type=str)
-    parser.add_argument("--port", help="RTU serial port", default='/dev/ttyUSB0', type=str)
+    parser.add_argument(
+        "--port", help="RTU serial port", default="/dev/ttyUSB0", type=str
+    )
     parser.add_argument("--baudrate", help="RTU baudrate", default=9600, type=int)
     parser.add_argument("--server_port", help="server port", default=5020, type=int)
     parser.add_argument("--server_ip", help="server IP", default="127.0.0.1", type=str)
-    parser.add_argument("--slaves", help="list of slaves to forward", type=int, nargs="+")
+    parser.add_argument(
+        "--slaves", help="list of slaves to forward", type=int, nargs="+"
+    )
 
     args = parser.parse_args()
 
     # set defaults
-    _logger.setLevel(args.log.upper() if args.log.lower() in logchoices else logging.INFO)
+    _logger.setLevel(
+        args.log.upper() if args.log.lower() in logchoices else logging.INFO
+    )
     if not args.slaves:
         args.slaves = {1, 2, 3}
     return args.port, args.baudrate, args.server_port, args.server_ip, args.slaves
diff --git a/examples/server_async.py b/examples/server_async.py
index cd7d97511..59e2f8657 100755
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -27,9 +27,9 @@
 The corresponding client can be started as:
     python3 client_sync.py
 """
-import os
 import asyncio
 import logging
+import os
 
 from examples.helper import get_commandline
 from pymodbus.datastore import (
diff --git a/examples/server_sync.py b/examples/server_sync.py
index ec7fc1b98..560cfab33 100755
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -31,8 +31,8 @@
 is just a thin cover on top of the async server and is in some aspects
 a lot slower.
 """
-import os
 import logging
+import os
 
 from examples.helper import get_commandline
 from examples.server_async import setup_server
diff --git a/pymodbus/bit_read_message.py b/pymodbus/bit_read_message.py
index be9d89e9b..6fcdb436e 100644
--- a/pymodbus/bit_read_message.py
+++ b/pymodbus/bit_read_message.py
@@ -3,11 +3,8 @@
 import struct
 
 from pymodbus.constants import Defaults
-from pymodbus.pdu import (
-    ModbusExceptions as merror,
-    ModbusRequest,
-    ModbusResponse,
-)
+from pymodbus.pdu import ModbusExceptions as merror
+from pymodbus.pdu import ModbusRequest, ModbusResponse
 from pymodbus.utilities import pack_bitstring, unpack_bitstring
 
 
diff --git a/pymodbus/bit_write_message.py b/pymodbus/bit_write_message.py
index 3d6cb10c7..2292a34fa 100644
--- a/pymodbus/bit_write_message.py
+++ b/pymodbus/bit_write_message.py
@@ -6,11 +6,8 @@
 import struct
 
 from pymodbus.constants import ModbusStatus
-from pymodbus.pdu import (
-    ModbusExceptions as merror,
-    ModbusRequest,
-    ModbusResponse,
-)
+from pymodbus.pdu import ModbusExceptions as merror
+from pymodbus.pdu import ModbusRequest, ModbusResponse
 from pymodbus.utilities import pack_bitstring, unpack_bitstring
 
 
diff --git a/pymodbus/client/__init__.py b/pymodbus/client/__init__.py
index 904de56d7..236dcd43b 100644
--- a/pymodbus/client/__init__.py
+++ b/pymodbus/client/__init__.py
@@ -2,11 +2,11 @@
 
 import external classes, to make them easier to use:
 """
+from pymodbus.client.base import ModbusBaseClient
 from pymodbus.client.serial import AsyncModbusSerialClient, ModbusSerialClient
 from pymodbus.client.tcp import AsyncModbusTcpClient, ModbusTcpClient
 from pymodbus.client.tls import AsyncModbusTlsClient, ModbusTlsClient
 from pymodbus.client.udp import AsyncModbusUdpClient, ModbusUdpClient
-from pymodbus.client.base import ModbusBaseClient
 
 
 # ---------------------------------------------------------------------------#
diff --git a/pymodbus/client/base.py b/pymodbus/client/base.py
index 500e6ad28..45a58f679 100644
--- a/pymodbus/client/base.py
+++ b/pymodbus/client/base.py
@@ -2,9 +2,9 @@
 from __future__ import annotations
 
 import asyncio
-from dataclasses import dataclass
 import logging
 import socket
+from dataclasses import dataclass
 
 from pymodbus.client.mixin import ModbusClientMixin
 from pymodbus.constants import Defaults
@@ -155,7 +155,7 @@ def is_socket_open(self) -> bool:
         raise NotImplementedException
 
     def idle_time(self) -> int:
-        """Time before initiatiating next transaction (call **sync**).
+        """Time before initiating next transaction (call **sync**).
 
         Applications can call message functions without checking idle_time(),
         this is done automatically.
diff --git a/pymodbus/client/mixin.py b/pymodbus/client/mixin.py
index b50a619d8..72a89456b 100644
--- a/pymodbus/client/mixin.py
+++ b/pymodbus/client/mixin.py
@@ -4,12 +4,12 @@
 
 import pymodbus.bit_read_message as pdu_bit_read
 import pymodbus.bit_write_message as pdu_bit_write
-from pymodbus.constants import Defaults
 import pymodbus.diag_message as pdu_diag
 import pymodbus.other_message as pdu_other_msg
-from pymodbus.pdu import ModbusRequest, ModbusResponse
 import pymodbus.register_read_message as pdu_reg_read
 import pymodbus.register_write_message as pdu_req_write
+from pymodbus.constants import Defaults
+from pymodbus.pdu import ModbusRequest, ModbusResponse
 from pymodbus.utilities import ModbusTransactionState
 
 
diff --git a/pymodbus/client/serial.py b/pymodbus/client/serial.py
index 4b64483b3..5dc68224f 100644
--- a/pymodbus/client/serial.py
+++ b/pymodbus/client/serial.py
@@ -1,16 +1,17 @@
 """Modbus client async serial communication."""
-from functools import partial
 import asyncio
-import time
 import logging
+import time
+from functools import partial
 
 from pymodbus.client.base import ModbusBaseClient, ModbusClientProtocol
 from pymodbus.constants import Defaults
+from pymodbus.exceptions import ConnectionException
 from pymodbus.framer import ModbusFramer
 from pymodbus.framer.rtu_framer import ModbusRtuFramer
-from pymodbus.exceptions import ConnectionException
 from pymodbus.utilities import ModbusTransactionState, hexlify_packets
 
+
 try:
     import serial
     from serial_asyncio import create_serial_connection
diff --git a/pymodbus/client/tcp.py b/pymodbus/client/tcp.py
index 1c5517a5f..aaf08fb6b 100644
--- a/pymodbus/client/tcp.py
+++ b/pymodbus/client/tcp.py
@@ -8,11 +8,12 @@
 
 from pymodbus.client.base import ModbusBaseClient, ModbusClientProtocol
 from pymodbus.constants import Defaults
+from pymodbus.exceptions import ConnectionException
 from pymodbus.framer import ModbusFramer
 from pymodbus.framer.socket_framer import ModbusSocketFramer
-from pymodbus.exceptions import ConnectionException
 from pymodbus.utilities import ModbusTransactionState
 
+
 _logger = logging.getLogger(__name__)
 
 
diff --git a/pymodbus/client/tls.py b/pymodbus/client/tls.py
index 637f05015..b88ed9bd2 100644
--- a/pymodbus/client/tls.py
+++ b/pymodbus/client/tls.py
@@ -9,6 +9,7 @@
 from pymodbus.framer import ModbusFramer
 from pymodbus.framer.tls_framer import ModbusTlsFramer
 
+
 _logger = logging.getLogger(__name__)
 
 
@@ -37,9 +38,7 @@ def sslctx_provider(
     sslctx.options |= ssl.OP_NO_SSLv3
     sslctx.options |= ssl.OP_NO_SSLv2
     if certfile and keyfile:
-        sslctx.load_cert_chain(
-            certfile=certfile, keyfile=keyfile, password=password
-        )
+        sslctx.load_cert_chain(certfile=certfile, keyfile=keyfile, password=password)
     return sslctx
 
 
diff --git a/pymodbus/client/udp.py b/pymodbus/client/udp.py
index dd4efe272..8ac652622 100644
--- a/pymodbus/client/udp.py
+++ b/pymodbus/client/udp.py
@@ -7,9 +7,10 @@
 
 from pymodbus.client.base import ModbusBaseClient, ModbusClientProtocol
 from pymodbus.constants import Defaults
+from pymodbus.exceptions import ConnectionException
 from pymodbus.framer import ModbusFramer
 from pymodbus.framer.socket_framer import ModbusSocketFramer
-from pymodbus.exceptions import ConnectionException
+
 
 _logger = logging.getLogger(__name__)
 
diff --git a/pymodbus/datastore/database/sql_datastore.py b/pymodbus/datastore/database/sql_datastore.py
index 6227e999f..a9f43b185 100644
--- a/pymodbus/datastore/database/sql_datastore.py
+++ b/pymodbus/datastore/database/sql_datastore.py
@@ -3,10 +3,10 @@
 import logging
 
 import sqlalchemy
+import sqlalchemy.types as sqltypes
 from sqlalchemy.schema import UniqueConstraint
 from sqlalchemy.sql import and_
 from sqlalchemy.sql.expression import bindparam
-import sqlalchemy.types as sqltypes
 
 from pymodbus.interfaces import IModbusSlaveContext
 
@@ -28,6 +28,10 @@ def __init__(self, *args, **kwargs):  # pylint: disable=unused-argument
 
         :param kwargs: Each element is a ModbusDataBlock
         """
+        self._engine = None
+        self._metadata = None
+        self._table = None
+        self._connection = None
         self.table = kwargs.get("table", "pymodbus")
         self.database = kwargs.get("database", "sqlite:///pymodbus.db")
         self._db_create(self.table, self.database)
diff --git a/pymodbus/device.py b/pymodbus/device.py
index f29906696..6ccd5ce1a 100644
--- a/pymodbus/device.py
+++ b/pymodbus/device.py
@@ -4,9 +4,10 @@
 maintained in the server context and the various methods
 should be inserted in the correct locations.
 """
+import struct
+
 # pylint: disable=missing-type-doc
 from collections import OrderedDict
-import struct
 
 from pymodbus.constants import DeviceInformation
 from pymodbus.interfaces import Singleton
diff --git a/pymodbus/factory.py b/pymodbus/factory.py
index ae2ecbb07..9ea58c24b 100644
--- a/pymodbus/factory.py
+++ b/pymodbus/factory.py
@@ -85,13 +85,9 @@
     ReportSlaveIdRequest,
     ReportSlaveIdResponse,
 )
-from pymodbus.pdu import (
-    ExceptionResponse,
-    IllegalFunctionRequest,
-    ModbusExceptions as ecode,
-    ModbusRequest,
-    ModbusResponse,
-)
+from pymodbus.pdu import ExceptionResponse, IllegalFunctionRequest
+from pymodbus.pdu import ModbusExceptions as ecode
+from pymodbus.pdu import ModbusRequest, ModbusResponse
 from pymodbus.register_read_message import (
     ReadHoldingRegistersRequest,
     ReadHoldingRegistersResponse,
diff --git a/pymodbus/file_message.py b/pymodbus/file_message.py
index 6dcdf7a78..20c765917 100644
--- a/pymodbus/file_message.py
+++ b/pymodbus/file_message.py
@@ -5,11 +5,8 @@
 # pylint: disable=missing-type-doc
 import struct
 
-from pymodbus.pdu import (
-    ModbusExceptions as merror,
-    ModbusRequest,
-    ModbusResponse,
-)
+from pymodbus.pdu import ModbusExceptions as merror
+from pymodbus.pdu import ModbusRequest, ModbusResponse
 
 
 # ---------------------------------------------------------------------------#
diff --git a/pymodbus/framer/ascii_framer.py b/pymodbus/framer/ascii_framer.py
index 62816638d..c01576195 100644
--- a/pymodbus/framer/ascii_framer.py
+++ b/pymodbus/framer/ascii_framer.py
@@ -1,8 +1,8 @@
 """Ascii_framer."""
 # pylint: disable=missing-type-doc
-from binascii import a2b_hex, b2a_hex
 import logging
 import struct
+from binascii import a2b_hex, b2a_hex
 
 from pymodbus.exceptions import ModbusIOException
 from pymodbus.framer import BYTE_ORDER, FRAME_HEADER, ModbusFramer
diff --git a/pymodbus/mei_message.py b/pymodbus/mei_message.py
index 686abb4d1..0fc386b27 100644
--- a/pymodbus/mei_message.py
+++ b/pymodbus/mei_message.py
@@ -4,11 +4,8 @@
 
 from pymodbus.constants import DeviceInformation, MoreData
 from pymodbus.device import DeviceInformationFactory, ModbusControlBlock
-from pymodbus.pdu import (
-    ModbusExceptions as merror,
-    ModbusRequest,
-    ModbusResponse,
-)
+from pymodbus.pdu import ModbusExceptions as merror
+from pymodbus.pdu import ModbusRequest, ModbusResponse
 
 
 _MCB = ModbusControlBlock()
diff --git a/pymodbus/pdu.py b/pymodbus/pdu.py
index c7b3ebe83..b761f58a5 100644
--- a/pymodbus/pdu.py
+++ b/pymodbus/pdu.py
@@ -99,6 +99,8 @@ def calculateRtuFrameSize(cls, buffer):  # pylint: disable=invalid-name
 class ModbusRequest(ModbusPDU):
     """Base class for a modbus request PDU."""
 
+    function_code = -1
+
     def __init__(self, unit=Defaults.Slave, **kwargs):
         """Proxy to the lower level initializer.
 
@@ -112,9 +114,7 @@ def doException(self, exception):  # pylint: disable=invalid-name
         :param exception: The exception to return
         :raises: An exception response
         """
-        exc = ExceptionResponse(
-            self.function_code, exception  # pylint: disable=no-member
-        )
+        exc = ExceptionResponse(self.function_code, exception)
         _logger.error(exc)
         return exc
 
diff --git a/pymodbus/register_read_message.py b/pymodbus/register_read_message.py
index b4a249374..cafcd439d 100644
--- a/pymodbus/register_read_message.py
+++ b/pymodbus/register_read_message.py
@@ -3,11 +3,8 @@
 import struct
 
 from pymodbus.constants import Defaults
-from pymodbus.pdu import (
-    ModbusExceptions as merror,
-    ModbusRequest,
-    ModbusResponse,
-)
+from pymodbus.pdu import ModbusExceptions as merror
+from pymodbus.pdu import ModbusRequest, ModbusResponse
 
 
 class ReadRegistersRequestBase(ModbusRequest):
diff --git a/pymodbus/register_write_message.py b/pymodbus/register_write_message.py
index c1b4fda78..1b64f3f2c 100644
--- a/pymodbus/register_write_message.py
+++ b/pymodbus/register_write_message.py
@@ -2,11 +2,8 @@
 # pylint: disable=missing-type-doc
 import struct
 
-from pymodbus.pdu import (
-    ModbusExceptions as merror,
-    ModbusRequest,
-    ModbusResponse,
-)
+from pymodbus.pdu import ModbusExceptions as merror
+from pymodbus.pdu import ModbusRequest, ModbusResponse
 
 
 class WriteSingleRegisterRequest(ModbusRequest):
diff --git a/pymodbus/repl/client/helper.py b/pymodbus/repl/client/helper.py
index cc7354785..ec13d8385 100644
--- a/pymodbus/repl/client/helper.py
+++ b/pymodbus/repl/client/helper.py
@@ -1,13 +1,13 @@
 """Helper Module for REPL actions."""
-from collections import OrderedDict
 import inspect
 
 # pylint: disable=missing-type-doc
 import json
+from collections import OrderedDict
 
+import pygments
 from prompt_toolkit import print_formatted_text
 from prompt_toolkit.formatted_text import HTML, PygmentsTokens
-import pygments
 from pygments.lexers.data import JsonLexer
 
 from pymodbus.payload import BinaryPayloadDecoder, Endian
diff --git a/pymodbus/repl/client/main.py b/pymodbus/repl/client/main.py
index a22afb220..f40ce155f 100644
--- a/pymodbus/repl/client/main.py
+++ b/pymodbus/repl/client/main.py
@@ -29,7 +29,10 @@
 from pygments.lexers.python import PythonLexer
 
 from pymodbus.exceptions import ParameterException
-from pymodbus.repl.client.completer import CmdCompleter, has_selected_completion
+from pymodbus.repl.client.completer import (
+    CmdCompleter,
+    has_selected_completion,
+)
 from pymodbus.repl.client.helper import CLIENT_ATTRIBUTES, Result
 from pymodbus.repl.client.mclient import ModbusSerialClient, ModbusTcpClient
 from pymodbus.transaction import (
@@ -121,7 +124,7 @@ def convert(self, value, param, ctx):
         return None
 
 
-def _process_args(args: list, string: bool=True):
+def _process_args(args: list, string: bool = True):
     """Internal function to parse arguments provided on command line.
 
     :param args: Array of argument values
diff --git a/pymodbus/repl/client/mclient.py b/pymodbus/repl/client/mclient.py
index 53e31b145..c76ce98b9 100644
--- a/pymodbus/repl/client/mclient.py
+++ b/pymodbus/repl/client/mclient.py
@@ -2,10 +2,8 @@
 # pylint: disable=missing-type-doc
 import functools
 
-from pymodbus.client import (
-    ModbusSerialClient as _ModbusSerialClient,
-    ModbusTcpClient as _ModbusTcpClient,
-)
+from pymodbus.client import ModbusSerialClient as _ModbusSerialClient
+from pymodbus.client import ModbusTcpClient as _ModbusTcpClient
 from pymodbus.constants import Defaults
 from pymodbus.diag_message import (
     ChangeAsciiInputDelimiterRequest,
@@ -74,7 +72,10 @@ class ExtendedRequestSupport:  # pylint: disable=(too-many-public-methods
     def _process_exception(resp, **kwargs):
         """Set internal process exception."""
         unit = kwargs.get("unit")
-        if unit == 0:  # pylint: disable=compare-to-zero,disable=consider-using-assignment-expr
+        if (
+            unit  # pylint: disable=compare-to-zero,disable=consider-using-assignment-expr
+            == 0
+        ):
             err = {"message": "Broadcast message, ignoring errors!!!"}
         else:
             if isinstance(resp, ExceptionResponse):  # pylint: disable=else-if-used
diff --git a/pymodbus/repl/server/main.py b/pymodbus/repl/server/main.py
index ae9079058..d438334be 100644
--- a/pymodbus/repl/server/main.py
+++ b/pymodbus/repl/server/main.py
@@ -2,9 +2,9 @@
 from __future__ import annotations
 
 import asyncio
-from enum import Enum
 import json
 import logging
+from enum import Enum
 from pathlib import Path
 from typing import List
 
diff --git a/pymodbus/server/__init__.py b/pymodbus/server/__init__.py
index cee5fbdcb..1a6150af7 100644
--- a/pymodbus/server/__init__.py
+++ b/pymodbus/server/__init__.py
@@ -5,10 +5,10 @@
 from pymodbus.server.async_io import (
     ServerAsyncStop,
     ServerStop,
+    StartAsyncSerialServer,
     StartAsyncTcpServer,
     StartAsyncTlsServer,
     StartAsyncUdpServer,
-    StartAsyncSerialServer,
     StartSerialServer,
     StartTcpServer,
     StartTlsServer,
diff --git a/pymodbus/server/async_io.py b/pymodbus/server/async_io.py
index b7cd09589..6191cbe5b 100755
--- a/pymodbus/server/async_io.py
+++ b/pymodbus/server/async_io.py
@@ -1,10 +1,10 @@
 """Implementation of a Threaded Modbus Server."""
 # pylint: disable=missing-type-doc
 import asyncio
-from binascii import b2a_hex
 import logging
-import traceback
 import ssl
+import traceback
+from binascii import b2a_hex
 from time import sleep
 
 from pymodbus.constants import Defaults
@@ -21,6 +21,7 @@
 )
 from pymodbus.utilities import hexlify_packets
 
+
 try:
     import serial
     from serial_asyncio import create_serial_connection
@@ -37,7 +38,7 @@
 # Allow access to server object, to e.g. make a shutdown
 # --------------------------------------------------------------------------- #
 _server_stopped = None  # pylint: disable=invalid-name
-_server_stop = None   # pylint: disable=invalid-name
+_server_stop = None  # pylint: disable=invalid-name
 
 
 def sslctx_provider(
@@ -72,6 +73,7 @@ def sslctx_provider(
 
     return sslctx
 
+
 # --------------------------------------------------------------------------- #
 # Protocol Handlers
 # --------------------------------------------------------------------------- #
@@ -891,8 +893,8 @@ async def serve_forever(self):
         """Start endless loop."""
         if self.device.startswith("socket:"):
             # Socket server means listen so start a socket server
-            parts = self.device[7:].split(':')
-            host_port = ('', int(parts[1]))
+            parts = self.device[7:].split(":")
+            host_port = ("", int(parts[1]))
             self.server = await asyncio.get_event_loop().create_server(
                 lambda: self.handler(self),
                 *host_port,
@@ -912,6 +914,7 @@ async def serve_forever(self):
 # Creation Factories
 # --------------------------------------------------------------------------- #
 
+
 async def _helper_run_server(server, custom_functions):
     """Help starting/stopping server."""
     global _server_stopped, _server_stop  # pylint: disable=global-statement,invalid-name
@@ -961,13 +964,7 @@ async def StartAsyncTcpServer(  # pylint: disable=invalid-name,dangerous-default
     :return: an initialized but inactive server object coroutine
     """
     framer = kwargs.pop("framer", ModbusSocketFramer)
-    server = ModbusTcpServer(
-        context,
-        framer,
-        identity,
-        address,
-        **kwargs
-    )
+    server = ModbusTcpServer(context, framer, identity, address, **kwargs)
 
     if defer_start:
         return server
@@ -1051,13 +1048,7 @@ async def StartAsyncUdpServer(  # pylint: disable=invalid-name,dangerous-default
     :param kwargs:
     """
     framer = kwargs.pop("framer", ModbusSocketFramer)
-    server = ModbusUdpServer(
-        context,
-        framer,
-        identity,
-        address,
-        **kwargs
-    )
+    server = ModbusUdpServer(context, framer, identity, address, **kwargs)
     if defer_start:
         return server
     await _helper_run_server(server, custom_functions)
@@ -1082,12 +1073,7 @@ async def StartAsyncSerialServer(  # pylint: disable=invalid-name,dangerous-defa
     :param kwargs: The rest
     """
     framer = kwargs.pop("framer", ModbusAsciiFramer)
-    server = ModbusSerialServer(
-        context,
-        framer,
-        identity=identity,
-        **kwargs
-    )
+    server = ModbusSerialServer(context, framer, identity=identity, **kwargs)
     if defer_start:
         return server
     await server.start()
diff --git a/pymodbus/transaction.py b/pymodbus/transaction.py
index d173d36e5..57b2c085e 100644
--- a/pymodbus/transaction.py
+++ b/pymodbus/transaction.py
@@ -1,11 +1,11 @@
 """Collection of transaction based abstractions."""
 # pylint: disable=missing-type-doc
-from functools import partial
 import logging
 import socket
 import struct
-from threading import RLock
 import time
+from functools import partial
+from threading import RLock
 
 from pymodbus.constants import Defaults
 from pymodbus.exceptions import (
@@ -505,7 +505,7 @@ def __iter__(self):
     def addTransaction(self, request, tid=None):
         """Add a transaction to the handler.
 
-        This holds the requets in case it needs to be resent.
+        This holds the requests in case it needs to be resent.
         After being sent, the request is removed.
 
         :param request: The request to hold on to
@@ -567,7 +567,7 @@ def __iter__(self):
     def addTransaction(self, request, tid=None):
         """Add a transaction to the handler.
 
-        This holds the requets in case it needs to be resent.
+        This holds the requests in case it needs to be resent.
         After being sent, the request is removed.
 
         :param request: The request to hold on to
diff --git a/pymodbus/utilities.py b/pymodbus/utilities.py
index 14076e427..6ede25d22 100644
--- a/pymodbus/utilities.py
+++ b/pymodbus/utilities.py
@@ -213,7 +213,7 @@ def computeLRC(data):  # pylint: disable=invalid-name
 
     This is only used on the serial ASCII
     modbus protocol. A full description of this implementation
-    can be found in appendex B of the serial line modbus description.
+    can be found in appendix B of the serial line modbus description.
 
     :param data: The data to apply a lrc to
     :returns: The calculated LRC
diff --git a/pymodbus/version.py b/pymodbus/version.py
index fd472575d..a21e83e51 100644
--- a/pymodbus/version.py
+++ b/pymodbus/version.py
@@ -47,6 +47,4 @@ def __str__(self):
 # Exported symbols
 # --------------------------------------------------------------------------- #
 
-__all__ = [
-    "version"
-]
+__all__ = ["version"]
diff --git a/requirements.txt b/requirements.txt
index 8ef5be05c..70251d182 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -53,21 +53,21 @@ sphinx-rtd-theme
 # -------------------------------------------------------------------
 # install:development]
 bandit==1.7.4
-black==22.3.0
-codespell==2.1.0
-coverage==6.4
-flake8==4.0.1
+black==22.10.0
+codespell==2.2.2
+coverage==6.5
+flake8==5.0.4
 flake8-docstrings==1.6.0
-flake8-noqa==1.2.2
+flake8-noqa==1.2.9
 flake8-comprehensions==3.10.0
 isort==5.10.1
 pep8==1.7.1
-pyflakes==2.4.0
+pyflakes==2.5.0
 pydocstyle==6.1.1
-pycodestyle==2.8.0
-pylint==2.14.5
-pytest==7.1.2
-pytest-asyncio==0.18.3
-pytest-cov==3.0.0
+pycodestyle==2.9.1
+pylint==2.15.4
+pytest==7.1.3
+pytest-asyncio==0.19.0
+pytest-cov==4.0.0
 pytest-timeout==2.1.0
-tox==3.25.0
+tox==3.26.0
diff --git a/setup.cfg b/setup.cfg
index 9c07b4484..eb0695efe 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -274,7 +274,7 @@ const-rgx=(([A-Z_][A-Z0-9_]*)|(__.*__))$
 
 # Naming style matching correct attribute names.
 attr-naming-style=snake_case
-attr-rgx=[a-z_][a-z0-9_]{2,}$
+attr-rgx=([A-Za-z_][A-Za-z0-9_]{2,30}|(__.*__))$
 
 # Naming style matching correct argument names.
 argument-naming-style=snake_case
@@ -386,7 +386,7 @@ max-parents=7
 ignored-parents=
 
 # Maximum number of attributes for a class (see R0902).
-max-attributes=11
+max-attributes=20
 
 # Minimum number of public methods for a class (see R0903).
 min-public-methods=2
@@ -543,20 +543,8 @@ omit =
 [isort]
 py_version=38
 profile=black
-line_length = 80
+line_length = 79
 lines_after_imports = 2
 known_local_folder =
     common
     contrib
-sections =
-    FUTURE
-    STDLIB
-    THIRDPARTY
-    FIRSTPARTY
-    LOCALFOLDER
-include_trailing_comma = true
-use_parentheses = true
-combine_as_imports = true
-force_sort_within_sections = true
-forced_separate = doc,examples,pymodbus,test
-known_first_party = doc,examples,pymodbus,test
diff --git a/test/test_bit_read_messages.py b/test/test_bit_read_messages.py
index 6b9beea3d..5af92a65c 100644
--- a/test/test_bit_read_messages.py
+++ b/test/test_bit_read_messages.py
@@ -7,9 +7,8 @@
 * Read Coils
 """
 import struct
-
-from test.conftest import MockContext
 import unittest
+from test.conftest import MockContext
 
 from pymodbus.bit_read_message import (
     ReadBitsRequestBase,
diff --git a/test/test_bit_write_messages.py b/test/test_bit_write_messages.py
index f4e40259c..fd40a53c1 100644
--- a/test/test_bit_write_messages.py
+++ b/test/test_bit_write_messages.py
@@ -6,8 +6,8 @@
 * Read/Write Discretes
 * Read Coils
 """
-from test.conftest import FakeList, MockContext
 import unittest
+from test.conftest import FakeList, MockContext
 
 from pymodbus.bit_write_message import (
     WriteMultipleCoilsRequest,
diff --git a/test/test_client.py b/test/test_client.py
index 46cc537f5..d55f8a7ca 100755
--- a/test/test_client.py
+++ b/test/test_client.py
@@ -2,26 +2,26 @@
 import asyncio
 import socket
 import ssl
-
 from test.conftest import return_as_coroutine, run_coroutine
 from unittest import mock
+
 import pytest
 
 import pymodbus.bit_read_message as pdu_bit_read
 import pymodbus.bit_write_message as pdu_bit_write
 import pymodbus.client as lib_client
+import pymodbus.diag_message as pdu_diag
+import pymodbus.other_message as pdu_other_msg
+import pymodbus.register_read_message as pdu_reg_read
+import pymodbus.register_write_message as pdu_req_write
 from pymodbus.client.base import ModbusBaseClient, ModbusClientProtocol
 from pymodbus.client.mixin import ModbusClientMixin
 from pymodbus.constants import Defaults
-import pymodbus.diag_message as pdu_diag
 from pymodbus.exceptions import ConnectionException, NotImplementedException
 from pymodbus.framer.ascii_framer import ModbusAsciiFramer
 from pymodbus.framer.rtu_framer import ModbusRtuFramer
 from pymodbus.framer.socket_framer import ModbusSocketFramer
 from pymodbus.framer.tls_framer import ModbusTlsFramer
-import pymodbus.other_message as pdu_other_msg
-import pymodbus.register_read_message as pdu_reg_read
-import pymodbus.register_write_message as pdu_req_write
 
 
 @pytest.mark.parametrize(
@@ -247,12 +247,10 @@ def test_client_instanciate(
     client.reset_delay()
     assert client.delay_ms == initial_delay
 
-    assert socket.AF_INET == client._get_address_family(  # pylint: disable=protected-access
-        "127.0.0.1"
-    )
-    assert socket.AF_INET6 == client._get_address_family(  # pylint: disable=protected-access
-        "::1"
-    )
+    rc1 = client._get_address_family("127.0.0.1")  # pylint: disable=protected-access
+    assert socket.AF_INET == rc1
+    rc2 = client._get_address_family("::1")  # pylint: disable=protected-access
+    assert socket.AF_INET6 == rc2
 
     # a successful execute
     client.connect = lambda: True
diff --git a/test/test_client_sync.py b/test/test_client_sync.py
index 37adc5ba3..e53ff1d65 100755
--- a/test/test_client_sync.py
+++ b/test/test_client_sync.py
@@ -1,9 +1,8 @@
 """Test client sync."""
-from itertools import count
 import ssl
-
-from test.conftest import mockSocket
 import unittest
+from itertools import count
+from test.conftest import mockSocket
 from unittest.mock import MagicMock, Mock, patch
 
 import serial
diff --git a/test/test_client_sync_diag.py b/test/test_client_sync_diag.py
index 220a1486d..69d8508f3 100755
--- a/test/test_client_sync_diag.py
+++ b/test/test_client_sync_diag.py
@@ -1,10 +1,9 @@
 """Test client sync diag."""
-from itertools import count
 import socket
-
 import unittest
-from unittest.mock import MagicMock, patch
+from itertools import count
 from test.test_client_sync import mockSocket
+from unittest.mock import MagicMock, patch
 
 from pymodbus.client.sync_diag import ModbusTcpDiagClient, get_client
 from pymodbus.exceptions import ConnectionException
diff --git a/test/test_examples.py b/test/test_examples.py
index af2bbe645..93c416b33 100755
--- a/test/test_examples.py
+++ b/test/test_examples.py
@@ -1,9 +1,9 @@
 """Test client async."""
 import asyncio
+import logging
 from dataclasses import dataclass
 from threading import Thread
 from time import sleep
-import logging
 
 import pytest
 import pytest_asyncio
@@ -11,10 +11,9 @@
 from examples.client_async import run_async_client, setup_async_client
 from examples.client_async_basic_calls import run_async_basic_calls
 from examples.client_async_extended_calls import run_async_ext_calls
-from examples.server_async import setup_server, run_async_server
+from examples.server_async import run_async_server, setup_server
 from examples.server_sync import run_sync_server
-
-from pymodbus.server import ServerStop, ServerAsyncStop
+from pymodbus.server import ServerAsyncStop, ServerStop
 from pymodbus.transaction import (
     ModbusAsciiFramer,
     ModbusBinaryFramer,
@@ -70,11 +69,7 @@ async def _helper_server(
     await ServerAsyncStop()
 
 
-async def run_client(
-    test_comm,
-    test_type,
-    args=Commandline
-):
+async def run_client(test_comm, test_type, args=Commandline):
     """Help run async client."""
 
     args.comm = test_comm
@@ -133,15 +128,12 @@ def test_exp_sync_simple(
     ],
 )
 async def test_exp_async_framer(  # pylint: disable=unused-argument
-    test_comm,
-    test_framer,
-    test_port_offset,
-    test_port,
-    mock_run_server,
-    test_type
+    test_comm, test_framer, test_port_offset, test_port, mock_run_server, test_type
 ):
     """Test client-server async with different framers and calls."""
-    if test_type == run_async_ext_calls and test_framer == ModbusRtuFramer:  # pylint: disable=comparison-with-callable
+    rc1 = test_type == run_async_ext_calls  # pylint: disable=comparison-with-callable
+    rc2 = test_framer == ModbusRtuFramer
+    if rc1 and rc2:
         return
     if test_comm == "serial":
         return
diff --git a/test/test_factory.py b/test/test_factory.py
index 30ba35d81..ddd9d2ee6 100644
--- a/test/test_factory.py
+++ b/test/test_factory.py
@@ -1,7 +1,7 @@
 """Test factory."""
 import unittest
 
-from pymodbus.exceptions import ModbusException, MessageRegisterException
+from pymodbus.exceptions import MessageRegisterException, ModbusException
 from pymodbus.factory import ClientDecoder, ServerDecoder
 from pymodbus.pdu import ModbusRequest, ModbusResponse
 
@@ -168,7 +168,7 @@ class CustomRequest(ModbusRequest):
 
             function_code = 0xFF
 
-        class NoCustomRequest():  # pylint: disable=too-few-public-methods
+        class NoCustomRequest:  # pylint: disable=too-few-public-methods
             """Custom request."""
 
             function_code = 0xFF
@@ -193,7 +193,7 @@ class CustomResponse(ModbusResponse):
 
             function_code = 0xFF
 
-        class NoCustomResponse():  # pylint: disable=too-few-public-methods
+        class NoCustomResponse:  # pylint: disable=too-few-public-methods
             """Custom request."""
 
             function_code = 0xFF
diff --git a/test/test_file_message.py b/test/test_file_message.py
index e649f08c4..49558bacf 100644
--- a/test/test_file_message.py
+++ b/test/test_file_message.py
@@ -6,8 +6,8 @@
 * Read/Write Discretes
 * Read Coils
 """
-from test.conftest import MockContext
 import unittest
+from test.conftest import MockContext
 
 from pymodbus.file_message import (
     FileRecord,
diff --git a/test/test_framers.py b/test/test_framers.py
index 68a3ade05..3206b3748 100644
--- a/test/test_framers.py
+++ b/test/test_framers.py
@@ -266,7 +266,11 @@ def test_rtu_incoming_packet(rtu_framer, data):  # pylint: disable=redefined-out
     """Test rtu process incoming packet."""
     buffer, units, reset_called, process_called = data
 
-    with patch.object(rtu_framer, "_process", wraps=rtu_framer._process) as mock_process, patch.object(  # pylint: disable=protected-access
+    with patch.object(
+        rtu_framer,
+        "_process",
+        wraps=rtu_framer._process,  # pylint: disable=protected-access
+    ) as mock_process, patch.object(
         rtu_framer, "resetFrame", wraps=rtu_framer.resetFrame
     ) as mock_reset:
         rtu_framer.processIncomingPacket(buffer, Mock(), units)
diff --git a/test/test_register_read_messages.py b/test/test_register_read_messages.py
index 100f62236..a873378fb 100644
--- a/test/test_register_read_messages.py
+++ b/test/test_register_read_messages.py
@@ -1,6 +1,6 @@
 """Test register read messages."""
-from test.conftest import FakeList, MockContext
 import unittest
+from test.conftest import FakeList, MockContext
 
 from pymodbus.pdu import ModbusExceptions
 from pymodbus.register_read_message import (
diff --git a/test/test_register_write_messages.py b/test/test_register_write_messages.py
index b0a54e6dd..a73398863 100644
--- a/test/test_register_write_messages.py
+++ b/test/test_register_write_messages.py
@@ -1,6 +1,6 @@
 """Test register write messages."""
-from test.conftest import MockContext, MockLastValuesContext
 import unittest
+from test.conftest import MockContext, MockLastValuesContext
 
 from pymodbus.payload import BinaryPayloadBuilder, Endian
 from pymodbus.pdu import ModbusExceptions
diff --git a/test/test_server_asyncio.py b/test/test_server_asyncio.py
index bf8f0e33c..2584b20a1 100755
--- a/test/test_server_asyncio.py
+++ b/test/test_server_asyncio.py
@@ -1,9 +1,9 @@
 """Test server asyncio."""
 import asyncio
-from asyncio import CancelledError
 import logging
 import ssl
 import unittest
+from asyncio import CancelledError
 from unittest.mock import AsyncMock, Mock, patch
 
 import pytest
diff --git a/test/test_transaction.py b/test/test_transaction.py
index 04f87cc36..4ac0aa34e 100755
--- a/test/test_transaction.py
+++ b/test/test_transaction.py
@@ -1,7 +1,7 @@
 """Test transaction."""
+import unittest
 from binascii import a2b_hex
 from itertools import count
-import unittest
 from unittest.mock import MagicMock, patch
 
 from pymodbus.exceptions import (
diff --git a/tox.ini b/tox.ini
index 720373ccf..61bf3bcdb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -34,7 +34,13 @@ commands =
 deps = -r requirements.txt
 ignore_errors = false
 commands =
-    isort examples pymodbus test
+    isort --recursive examples pymodbus test
+
+[testenv:isort_CI]
+deps = -r requirements.txt
+ignore_errors = false
+commands =
+    isort --check --recursive examples pymodbus test
 
 [testenv:bandit]
 deps = -r requirements.txt
@@ -44,14 +50,22 @@ commands =
 
 [testenv:flake8]
 deps = -r requirements.txt
+ignore_errors = false
 commands =
     flake8 doc/ examples/ pymodbus/ test/
 
 [testenv:black]
 deps = -r requirements.txt
+ignore_errors = false
 commands =
     black --safe --quiet examples/ pymodbus/ test/
 
+[testenv:black_CI]
+deps = -r requirements.txt
+ignore_errors = false
+commands =
+    black --check --safe --quiet examples/ pymodbus/ test/
+
 [testenv:docs]
 allowlist_externals =
     make
@@ -68,4 +82,3 @@ commands =
     ls -la coverage_reports
     coverage combine coverage_reports
     coverage report --fail-under=60 --ignore-errors
-