Fix static typing

Fixed the following files:

pycardano/certificate.py
pycardano/cip/cip8.py
pycardano/coinselection.py
pycardano/key.py
pycardano/metadata.py
pycardano/plutus.py
pycardano/serialization.py
pycardano/transaction.py
pycardano/txbuilder.py
pycardano/utils.py
pycardano/witness.py

pycardano/certificate.py

@@ -1,5 +1,5 @@
 from dataclasses import dataclass, field
-from typing import Union
+from typing import Optional, Union
 
 from pycardano.hash import PoolKeyHash, ScriptHash, VerificationKeyHash
 from pycardano.serialization import ArrayCBORSerializable
@@ -16,7 +16,7 @@
 @dataclass(repr=False)
 class StakeCredential(ArrayCBORSerializable):
 
-    _CODE: int = field(init=False, default=None)
+    _CODE: Optional[int] = field(init=False, default=None)
 
     credential: Union[VerificationKeyHash, ScriptHash]
 

pycardano/cip/cip8.py

@@ -119,13 +119,19 @@ def verify(
     if attach_cose_key:
         # The cose key is attached as a dict object which contains the verification key
         # the headers of the signature are emtpy
+        assert isinstance(
+            signed_message, dict
+        ), "signed_message must be a dict if attach_cose_key is True"
         key = signed_message.get("key")
-        signed_message = signed_message.get("signature")
+        signed_message = signed_message.get("signature")  # type: ignore
 
     else:
         key = ""  # key will be extracted later from the payload headers
 
     # Add back the "D2" header byte and decode
+    assert isinstance(
+        signed_message, str
+    ), "signed_message must be a hex string at this point"
     decoded_message = CoseMessage.decode(bytes.fromhex("d2" + signed_message))
 
     # generate/extract the cose key
@@ -146,6 +152,9 @@ def verify(
 
     else:
         # i,e key is sent separately
+        assert isinstance(
+            key, str
+        ), "key must be a hex string if attach_cose_key is True"
         cose_key = CoseKey.decode(bytes.fromhex(key))
         verification_key = cose_key[OKPKpX]
 

pycardano/coinselection.py

@@ -33,9 +33,9 @@ def select(
         utxos: List[UTxO],
         outputs: List[TransactionOutput],
         context: ChainContext,
-        max_input_count: int = None,
-        include_max_fee: bool = True,
-        respect_min_utxo: bool = True,
+        max_input_count: Optional[int] = None,
+        include_max_fee: Optional[bool] = True,
+        respect_min_utxo: Optional[bool] = True,
     ) -> Tuple[List[UTxO], Value]:
         """From an input list of UTxOs, select a subset of UTxOs whose sum (including ADA and multi-assets)
         is equal to or larger than the sum of a set of outputs.
@@ -115,7 +115,11 @@ def select(
             if change.coin < min_change_amount:
                 additional, _ = self.select(
                     available,
-                    [TransactionOutput(None, min_change_amount - change.coin)],
+                    [
+                        TransactionOutput(
+                            _FAKE_ADDR, Value(min_change_amount - change.coin)
+                        )
+                    ],
                     context,
                     max_input_count - len(selected) if max_input_count else None,
                     include_max_fee=False,
@@ -230,13 +234,13 @@ def _improve(
         remaining: List[UTxO],
         ideal: Value,
         upper_bound: Value,
-        max_input_count: int,
+        max_input_count: Optional[int] = None,
     ):
         if not remaining or self._find_diff_by_former(ideal, selected_amount) <= 0:
             # In case where there is no remaining UTxOs or we already selected more than ideal,
             # we cannot improve by randomly adding more UTxOs, therefore return immediate.
             return
-        if max_input_count and len(selected) > max_input_count:
+        if max_input_count is not None and len(selected) > max_input_count:
             raise MaxInputCountExceededException(
                 f"Max input count: {max_input_count} exceeded!"
             )
@@ -269,9 +273,9 @@ def select(
         utxos: List[UTxO],
         outputs: List[TransactionOutput],
         context: ChainContext,
-        max_input_count: int = None,
-        include_max_fee: bool = True,
-        respect_min_utxo: bool = True,
+        max_input_count: Optional[int] = None,
+        include_max_fee: Optional[bool] = True,
+        respect_min_utxo: Optional[bool] = True,
     ) -> Tuple[List[UTxO], Value]:
         # Shallow copy the list
         remaining = list(utxos)
@@ -284,7 +288,7 @@ def select(
         request_sorted = sorted(assets, key=self._get_single_asset_val, reverse=True)
 
         # Phase 1 - random select
-        selected = []
+        selected: List[UTxO] = []
         selected_amount = Value()
         for r in request_sorted:
             self._random_select_subset(r, remaining, selected, selected_amount)
@@ -321,7 +325,11 @@ def select(
             if change.coin < min_change_amount:
                 additional, _ = self.select(
                     remaining,
-                    [TransactionOutput(None, min_change_amount - change.coin)],
+                    [
+                        TransactionOutput(
+                            _FAKE_ADDR, Value(min_change_amount - change.coin)
+                        )
+                    ],
                     context,
                     max_input_count - len(selected) if max_input_count else None,
                     include_max_fee=False,

pycardano/key.py

@@ -4,7 +4,7 @@
 
 import json
 import os
-from typing import Type
+from typing import Optional, Type
 
 from nacl.encoding import RawEncoder
 from nacl.hash import blake2b
@@ -41,7 +41,12 @@ class Key(CBORSerializable):
     KEY_TYPE = ""
     DESCRIPTION = ""
 
-    def __init__(self, payload: bytes, key_type: str = None, description: str = None):
+    def __init__(
+        self,
+        payload: bytes,
+        key_type: Optional[str] = None,
+        description: Optional[str] = None,
+    ):
         self._payload = payload
         self._key_type = key_type or self.KEY_TYPE
         self._description = description or self.KEY_TYPE
@@ -83,7 +88,7 @@ def to_json(self) -> str:
         )
 
     @classmethod
-    def from_json(cls, data: str, validate_type=False) -> Key:
+    def from_json(cls: Type[Key], data: str, validate_type=False) -> Key:
         """Restore a key from a JSON string.
 
         Args:
@@ -105,8 +110,12 @@ def from_json(cls, data: str, validate_type=False) -> Key:
                 f"Expect key type: {cls.KEY_TYPE}, got {obj['type']} instead."
             )
 
+        k = cls.from_cbor(obj["cborHex"])
+
+        assert isinstance(k, cls)
+
         return cls(
-            cls.from_cbor(obj["cborHex"]).payload,
+            k.payload,
             key_type=obj["type"],
             description=obj["description"],
         )
@@ -244,19 +253,19 @@ class PaymentExtendedVerificationKey(ExtendedVerificationKey):
 
 
 class PaymentKeyPair:
-    def __init__(
-        self, signing_key: PaymentSigningKey, verification_key: PaymentVerificationKey
-    ):
+    def __init__(self, signing_key: SigningKey, verification_key: VerificationKey):
         self.signing_key = signing_key
         self.verification_key = verification_key
 
     @classmethod
-    def generate(cls) -> PaymentKeyPair:
+    def generate(cls: Type[PaymentKeyPair]) -> PaymentKeyPair:
         signing_key = PaymentSigningKey.generate()
         return cls.from_signing_key(signing_key)
 
     @classmethod
-    def from_signing_key(cls, signing_key: PaymentSigningKey) -> PaymentKeyPair:
+    def from_signing_key(
+        cls: Type[PaymentKeyPair], signing_key: SigningKey
+    ) -> PaymentKeyPair:
         return cls(signing_key, PaymentVerificationKey.from_signing_key(signing_key))
 
     def __eq__(self, other):
@@ -288,17 +297,17 @@ class StakeExtendedVerificationKey(ExtendedVerificationKey):
 
 
 class StakeKeyPair:
-    def __init__(
-        self, signing_key: StakeSigningKey, verification_key: StakeVerificationKey
-    ):
+    def __init__(self, signing_key: SigningKey, verification_key: VerificationKey):
         self.signing_key = signing_key
         self.verification_key = verification_key
 
     @classmethod
-    def generate(cls) -> StakeKeyPair:
+    def generate(cls: Type[StakeKeyPair]) -> StakeKeyPair:
         signing_key = StakeSigningKey.generate()
         return cls.from_signing_key(signing_key)
 
     @classmethod
-    def from_signing_key(cls, signing_key: StakeSigningKey) -> StakeKeyPair:
+    def from_signing_key(
+        cls: Type[StakeKeyPair], signing_key: SigningKey
+    ) -> StakeKeyPair:
         return cls(signing_key, StakeVerificationKey.from_signing_key(signing_key))

pycardano/metadata.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass, field
-from typing import Any, ClassVar, List, Type, Union
+from typing import Any, ClassVar, List, Optional, Type, Union
 
 from cbor2 import CBORTag
 from nacl.encoding import RawEncoder
@@ -20,7 +20,7 @@
     list_hook,
 )
 
-__all__ = ["Metadata", "ShellayMarryMetadata", "AlonzoMetadata", "AuxiliaryData"]
+__all__ = ["Metadata", "ShelleyMarryMetadata", "AlonzoMetadata", "AuxiliaryData"]
 
 
 class Metadata(DictCBORSerializable):
@@ -68,9 +68,9 @@ def __init__(self, *args, **kwargs):
 
 
 @dataclass
-class ShellayMarryMetadata(ArrayCBORSerializable):
+class ShelleyMarryMetadata(ArrayCBORSerializable):
     metadata: Metadata
-    native_scripts: List[NativeScript] = field(
+    native_scripts: Optional[List[NativeScript]] = field(
         default=None, metadata={"object_hook": list_hook(NativeScript)}
     )
 
@@ -79,12 +79,14 @@ class ShellayMarryMetadata(ArrayCBORSerializable):
 class AlonzoMetadata(MapCBORSerializable):
     TAG: ClassVar[int] = 259
 
-    metadata: Metadata = field(default=None, metadata={"optional": True, "key": 0})
-    native_scripts: List[NativeScript] = field(
+    metadata: Optional[Metadata] = field(
+        default=None, metadata={"optional": True, "key": 0}
+    )
+    native_scripts: Optional[List[NativeScript]] = field(
         default=None,
         metadata={"optional": True, "key": 1, "object_hook": list_hook(NativeScript)},
     )
-    plutus_scripts: List[bytes] = field(
+    plutus_scripts: Optional[List[bytes]] = field(
         default=None, metadata={"optional": True, "key": 2}
     )
 
@@ -107,23 +109,23 @@ def from_primitive(cls: Type[AlonzoMetadata], value: CBORTag) -> AlonzoMetadata:
 
 @dataclass
 class AuxiliaryData(CBORSerializable):
-    data: Union[Metadata, ShellayMarryMetadata, AlonzoMetadata]
+    data: Union[Metadata, ShelleyMarryMetadata, AlonzoMetadata]
 
     def to_primitive(self) -> Primitive:
         return self.data.to_primitive()
 
     @classmethod
     def from_primitive(cls: Type[AuxiliaryData], value: Primitive) -> AuxiliaryData:
-        for t in [AlonzoMetadata, ShellayMarryMetadata, Metadata]:
+        for t in [AlonzoMetadata, ShelleyMarryMetadata, Metadata]:
             # The schema of metadata in different eras are mutually exclusive, so we can try deserializing
             # them one by one without worrying about mismatch.
             try:
-                return AuxiliaryData(t.from_primitive(value))
+                return AuxiliaryData(t.from_primitive(value))  # type: ignore
             except DeserializeException:
                 pass
         raise DeserializeException(f"Couldn't parse auxiliary data: {value}")
 
     def hash(self) -> AuxiliaryDataHash:
         return AuxiliaryDataHash(
-            blake2b(self.to_cbor("bytes"), AUXILIARY_DATA_HASH_SIZE, encoder=RawEncoder)
+            blake2b(self.to_cbor("bytes"), AUXILIARY_DATA_HASH_SIZE, encoder=RawEncoder)  # type: ignore
         )

pycardano/plutus.py

@@ -21,6 +21,7 @@
     CBORSerializable,
     DictCBORSerializable,
     IndefiniteList,
+    Primitive,
     RawCBOR,
     default_encoder,
     limit_primitive_type,
@@ -39,6 +40,7 @@
     "PlutusV2Script",
     "RawPlutusData",
     "Redeemer",
+    "ScriptType",
     "datum_hash",
     "plutus_script_hash",
     "script_hash",
@@ -471,7 +473,7 @@ def __post_init__(self):
                 )
 
     def to_shallow_primitive(self) -> CBORTag:
-        primitives = super().to_shallow_primitive()
+        primitives: Primitive = super().to_shallow_primitive()
         if primitives:
             primitives = IndefiniteList(primitives)
         tag = get_tag(self.CONSTR_ID)
@@ -544,7 +546,7 @@ def _dfs(obj):
         return json.dumps(_dfs(self), **kwargs)
 
     @classmethod
-    def from_dict(cls: PlutusData, data: dict) -> PlutusData:
+    def from_dict(cls: Type[PlutusData], data: dict) -> PlutusData:
         """Convert a dictionary to PlutusData
 
         Args:
@@ -606,7 +608,7 @@ def _dfs(obj):
         return _dfs(data)
 
     @classmethod
-    def from_json(cls: PlutusData, data: str) -> PlutusData:
+    def from_json(cls: Type[PlutusData], data: str) -> PlutusData:
         """Restore a json encoded string to a PlutusData.
 
         Args:
@@ -701,7 +703,7 @@ class Redeemer(ArrayCBORSerializable):
 
     data: Any
 
-    ex_units: ExecutionUnits = None
+    ex_units: Optional[ExecutionUnits] = None
 
     @classmethod
     @limit_primitive_type(list)
@@ -729,13 +731,23 @@ def plutus_script_hash(
     return script_hash(script)
 
 
-def script_hash(
-    script: Union[bytes, NativeScript, PlutusV1Script, PlutusV2Script]
-) -> ScriptHash:
+class PlutusV1Script(bytes):
+    pass
+
+
+class PlutusV2Script(bytes):
+    pass
+
+
+ScriptType = Union[bytes, NativeScript, PlutusV1Script, PlutusV2Script]
+"""Script type. A Union type that contains all valid script types."""
+
+
+def script_hash(script: ScriptType) -> ScriptHash:
     """Calculates the hash of a script, which could be either native script or plutus script.
 
     Args:
-        script (Union[bytes, NativeScript, PlutusV1Script, PlutusV2Script]): A script.
+        script (ScriptType): A script.
 
     Returns:
         ScriptHash: blake2b hash of the script.
@@ -752,11 +764,3 @@ def script_hash(
         )
     else:
         raise TypeError(f"Unexpected script type: {type(script)}")
-
-
-class PlutusV1Script(bytes):
-    pass
-
-
-class PlutusV2Script(bytes):
-    pass