Resolve new mypy errors found in python3.8

Author: cffls

pycardano/cip/cip8.py

@@ -117,7 +117,7 @@ def sign(
             OKPKpX: verification_key.payload,  # public key
         }
 
-        signed_message = {
+        signed_message = {  # type: ignore
             "signature": signed_message,
             "key": CoseKey.from_dict(key_to_return).encode().hex(),
         }

pycardano/plutus.py

@@ -62,7 +62,7 @@ class CostModels(DictCBORSerializable):
     VALUE_TYPE = dict
 
     def to_shallow_primitive(self) -> dict:
-        result = {}
+        result: dict[bytes, Union[typing.List[Any], bytes]] = {}
         for language in sorted(self.keys()):
             cost_model = self[language]
             if language == 0:
@@ -788,7 +788,7 @@ def __deepcopy__(self, memo):
 class RawPlutusData(CBORSerializable):
     data: RawDatum
 
-    def to_primitive(self) -> RawDatum:
+    def to_primitive(self) -> Primitive:
         def _dfs(obj):
             if isinstance(obj, list) and obj:
                 return IndefiniteList([_dfs(item) for item in obj])

pycardano/serialization.py

@@ -98,7 +98,6 @@ class RawCBOR:
     dict,
     defaultdict,
     OrderedDict,
-    undefined.__class__,
     datetime,
     re.Pattern,
     CBORSimpleValue,
@@ -108,6 +107,7 @@ class RawCBOR:
     frozendict,
     FrozenList,
     IndefiniteFrozenList,
+    ByteString,
 ]
 
 PRIMITIVE_TYPES = (
@@ -481,7 +481,7 @@ def from_cbor(cls, payload: Union[str, bytes]) -> CBORSerializable:
         """
         if type(payload) == str:
             payload = bytes.fromhex(payload)
-        value = loads(payload)
+        value = loads(payload)  # type: ignore
         return cls.from_primitive(value)
 
     def __repr__(self):
@@ -639,7 +639,7 @@ class ArrayCBORSerializable(CBORSerializable):
         Test2(c='c', test1=Test1(a='a', b=None))
     """
 
-    def to_shallow_primitive(self) -> List[Primitive]:
+    def to_shallow_primitive(self) -> Primitive:
         """
         Returns:
             :const:`Primitive`: A CBOR primitive.

pycardano/transaction.py

@@ -289,7 +289,8 @@ def __post_init__(self):
         else:
             self._TYPE = 1
 
-    def to_shallow_primitive(self) -> List[Primitive]:
+    def to_shallow_primitive(self) -> Primitive:
+        data: Union[CBORTag, DatumHash]
         if self._TYPE == 1:
             data = CBORTag(24, cbor2.dumps(self.datum, default=default_encoder))
         else: