Remove typing guards

Since we now require Python 3.5+, we can assume that the `typing` module
is available.  The guards can also be removed because importing that
module is cheap.  This simplifies the code.

Author: bbc2

requirements.txt

@@ -1,5 +1,4 @@
 bumpversion
-typing; python_version<"3.5"
 click
 flake8>=2.2.3
 ipython

src/dotenv/__init__.py

@@ -1,8 +1,7 @@
-from .compat import IS_TYPE_CHECKING
-from .main import load_dotenv, get_key, set_key, unset_key, find_dotenv, dotenv_values
+from typing import Any, Optional
 
-if IS_TYPE_CHECKING:
-    from typing import Any, Optional
+from .main import (dotenv_values, find_dotenv, get_key, load_dotenv, set_key,
+                   unset_key)
 
 
 def load_ipython_extension(ipython):

src/dotenv/cli.py

@@ -1,6 +1,7 @@
 import os
 import sys
 from subprocess import Popen
+from typing import Any, Dict, List
 
 try:
     import click
@@ -9,13 +10,9 @@
                      'Run pip install "python-dotenv[cli]" to fix this.')
     sys.exit(1)
 
-from .compat import IS_TYPE_CHECKING
 from .main import dotenv_values, get_key, set_key, unset_key
 from .version import __version__
 
-if IS_TYPE_CHECKING:
-    from typing import Any, List, Dict
-
 
 @click.group()
 @click.option('-f', '--file', default=os.path.join(os.getcwd(), '.env'),

src/dotenv/compat.py

@@ -6,20 +6,18 @@
 import tempfile
 from collections import OrderedDict
 from contextlib import contextmanager
+from typing import (IO, Dict, Iterable, Iterator, Mapping, Optional, Text,
+                    Tuple, Union)
 
-from .compat import IS_TYPE_CHECKING
 from .parser import Binding, parse_stream
 from .variables import parse_variables
 
 logger = logging.getLogger(__name__)
 
-if IS_TYPE_CHECKING:
-    from typing import (IO, Dict, Iterable, Iterator, Mapping, Optional, Text,
-                        Tuple, Union)
-    if sys.version_info >= (3, 6):
-        _PathLike = os.PathLike
-    else:
-        _PathLike = Text
+if sys.version_info >= (3, 6):
+    _PathLike = os.PathLike
+else:
+    _PathLike = Text
 
 
 def with_warn_for_invalid_lines(mappings):

src/dotenv/main.py

@@ -1,13 +1,7 @@
 import codecs
 import re
-
-from .compat import IS_TYPE_CHECKING
-
-if IS_TYPE_CHECKING:
-    from typing import (  # noqa:F401
-        IO, Iterator, Match, NamedTuple, Optional, Pattern, Sequence, Text,
-        Tuple
-    )
+from typing import (IO, Iterator, Match, NamedTuple, Optional,  # noqa:F401
+                    Pattern, Sequence, Text, Tuple)
 
 
 def make_regex(string, extra_flags=0):
@@ -32,47 +26,23 @@ def make_regex(string, extra_flags=0):
 _single_quote_escapes = make_regex(r"\\[\\']")
 
 
-try:
-    # this is necessary because we only import these from typing
-    # when we are type checking, and the linter is upset if we
-    # re-import
-    import typing
-
-    Original = typing.NamedTuple(
-        "Original",
-        [
-            ("string", typing.Text),
-            ("line", int),
-        ],
-    )
-
-    Binding = typing.NamedTuple(
-        "Binding",
-        [
-            ("key", typing.Optional[typing.Text]),
-            ("value", typing.Optional[typing.Text]),
-            ("original", Original),
-            ("error", bool),
-        ],
-    )
-except (ImportError, AttributeError):
-    from collections import namedtuple
-    Original = namedtuple(  # type: ignore
-        "Original",
-        [
-            "string",
-            "line",
-        ],
-    )
-    Binding = namedtuple(  # type: ignore
-        "Binding",
-        [
-            "key",
-            "value",
-            "original",
-            "error",
-        ],
-    )
+Original = NamedTuple(
+    "Original",
+    [
+        ("string", Text),
+        ("line", int),
+    ],
+)
+
+Binding = NamedTuple(
+    "Binding",
+    [
+        ("key", Optional[Text]),
+        ("value", Optional[Text]),
+        ("original", Original),
+        ("error", bool),
+    ],
+)
 
 
 class Position:

src/dotenv/parser.py

@@ -1,11 +1,6 @@
 import re
 from abc import ABCMeta
-
-from .compat import IS_TYPE_CHECKING
-
-if IS_TYPE_CHECKING:
-    from typing import Iterator, Mapping, Optional, Pattern, Text
-
+from typing import Iterator, Mapping, Optional, Pattern, Text
 
 _posix_variable = re.compile(
     r"""