diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 3a9975eb..62f87640 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -15,17 +15,13 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest]
         python-version: [3.7, 3.8, 3.9, '3.10', '3.11']
-        exclude:
-          # excludes python 3.11 on macOS
-          - os: macos-latest
-            python-version: '3.11'
 
     steps:
       - uses: actions/checkout@v3
       - name: Install poetry
         run: pipx install poetry
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v3
+        uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
           cache: 'poetry'
diff --git a/pycardano/serialization.py b/pycardano/serialization.py
index c3743c95..5e40a150 100644
--- a/pycardano/serialization.py
+++ b/pycardano/serialization.py
@@ -568,7 +568,7 @@ class MapCBORSerializable(CBORSerializable):
 
         Basic usage:
 
-        >>> from dataclasses import dataclass
+        >>> from dataclasses import dataclass, field
         >>> @dataclass
         ... class Test1(MapCBORSerializable):
         ...     a: str=""
@@ -576,7 +576,7 @@ class MapCBORSerializable(CBORSerializable):
         >>> @dataclass
         ... class Test2(MapCBORSerializable):
         ...     c: str=None
-        ...     test1: Test1=Test1()
+        ...     test1: Test1=field(default_factory=Test1)
         >>> t = Test2(test1=Test1(a="a"))
         >>> t
         Test2(c=None, test1=Test1(a='a', b=''))
@@ -600,7 +600,7 @@ class MapCBORSerializable(CBORSerializable):
         >>> @dataclass
         ... class Test2(MapCBORSerializable):
         ...     c: str=field(default=None, metadata={"key": "0", "optional": True})
-        ...     test1: Test1=field(default=Test1(), metadata={"key": "1"})
+        ...     test1: Test1=field(default_factory=Test1, metadata={"key": "1"})
         >>> t = Test2(test1=Test1(a="a"))
         >>> t
         Test2(c=None, test1=Test1(a='a', b=''))
diff --git a/test/pycardano/test_serialization.py b/test/pycardano/test_serialization.py
index d406de75..0f236980 100644
--- a/test/pycardano/test_serialization.py
+++ b/test/pycardano/test_serialization.py
@@ -87,7 +87,7 @@ class Test1(MapCBORSerializable):
     @dataclass
     class Test2(MapCBORSerializable):
         c: str = None
-        test1: Test1 = Test1()
+        test1: Test1 = field(default_factory=Test1)
 
     t = Test2(test1=Test1(a="a"))
     assert t.to_cbor() == "a26163f6657465737431a261616161616260"
@@ -103,7 +103,7 @@ class Test1(MapCBORSerializable):
     @dataclass
     class Test2(MapCBORSerializable):
         c: str = field(default=None, metadata={"key": "0", "optional": True})
-        test1: Test1 = field(default=Test1(), metadata={"key": "1"})
+        test1: Test1 = field(default_factory=Test1, metadata={"key": "1"})
 
     t = Test2(test1=Test1(a="a"))
     assert t.to_primitive() == {"1": {"0": "a", "1": ""}}