mypy: comply with strict mode and resolve all 'type: ignore' cases

Tested with mypy 1.5.1 on Python 3.11.

This changes `ByteString` into `Union[bytes, bytearray, memoryview]`.
See python/cpython#91896.

Python 3.11 documentation on `typing.ByteString`:

> Deprecated since version 3.9, will be removed in version 3.14: Prefer
> typing_extensions.Buffer, or a union like
> `bytes | bytearray | memoryview`.

Python 3.8 documentation on `typing.ByteString` [2]:

> This type represents the types `bytes`, `bytearray`, and `memoryview`
> of byte sequences.
>
> As a shorthand for this type, `bytes` can be used to annotate
> arguments of any of the types mentioned above.

[1]: https://docs.python.org/3.11/library/typing.html#typing.ByteString
[2]: https://docs.python.org/3.8/library/typing.html#typing.ByteString

Author: Gert van Dijk

crc.py

@@ -11,7 +11,6 @@
 from dataclasses import dataclass
 from typing import (
     BinaryIO,
-    ByteString,
     Iterable,
     Iterator,
     List,
@@ -62,15 +61,15 @@ def __getitem__(self, index: int) -> int:
     def __iter__(self) -> Iterator[int]:
         return (self[i] for i in range(0, len(self)))
 
-    def __int__(self):
+    def __int__(self) -> int:
         return self.value
 
     @property
     def value(self) -> int:
         return self._value & Byte.BIT_MASK
 
     @value.setter
-    def value(self, value) -> None:
+    def value(self, value: int) -> None:
         self._value = value & Byte.BIT_MASK
 
     def reversed(self) -> "Byte":
@@ -91,7 +90,7 @@ class AbstractRegister(metaclass=abc.ABCMeta):
     """
 
     @abc.abstractmethod
-    def init(self):
+    def init(self) -> None:
         """
         Initializes the crc register.
         """
@@ -175,7 +174,7 @@ def __init__(self, configuration: Configuration):
         if isinstance(configuration, enum.Enum):
             configuration = configuration.value
         self._topbit = 1 << (configuration.width - 1)
-        self._bitmask = 2**configuration.width - 1
+        self._bitmask = int(2**configuration.width - 1)
         self._config = configuration
         self._register = configuration.init_value & self._bitmask
 
@@ -260,7 +259,7 @@ def register(self) -> int:
         return self._register & self._bitmask
 
     @register.setter
-    def register(self, value) -> None:
+    def register(self, value: int) -> None:
         self._register = value & self._bitmask
 
 
@@ -368,7 +367,15 @@ def __init__(self, configuration: Configuration, optimized: bool = False):
         self._crc_register = klass(configuration)
 
     def checksum(
-        self, data: Union[int, ByteString, BinaryIO, Iterable[ByteString]]
+        self,
+        data: Union[
+            int,
+            bytes,
+            bytearray,
+            memoryview,
+            BinaryIO,
+            Iterable[Union[bytes, bytearray, memoryview]],
+        ],
     ) -> int:
         """
         Calculates the checksum for the given data.
@@ -386,7 +393,14 @@ def checksum(
 
     def verify(
         self,
-        data: Union[int, ByteString, BinaryIO, Iterable[ByteString]],
+        data: Union[
+            int,
+            bytes,
+            bytearray,
+            memoryview,
+            BinaryIO,
+            Iterable[Union[bytes, bytearray, memoryview]],
+        ],
         expected: int,
     ) -> bool:
         """
@@ -404,13 +418,22 @@ def verify(
 
 
 def _bytes_generator(
-    data: Union[int, ByteString, BinaryIO, Iterable[ByteString]]  # type: ignore
+    data: Union[
+        int,
+        bytes,
+        bytearray,
+        memoryview,
+        BinaryIO,
+        Iterable[Union[bytes, bytearray, memoryview]],
+    ]
 ) -> Iterable[bytes]:
     if isinstance(data, int):
         yield data.to_bytes(1, "big")
-    elif isinstance(data, ByteString):  # type: ignore
-        yield bytes(data)  # type: ignore
-    elif isinstance(data, (Iterable, BinaryIO)):  # type: ignore
+    elif isinstance(data, bytes):
+        yield data
+    elif isinstance(data, (bytearray, memoryview)):
+        yield bytes(data)
+    elif isinstance(data, (Iterable, BinaryIO)):
         yield from (bytes(e) for e in data)
     else:
         raise TypeError(f"Unsupported parameter type: {type(data)}")
@@ -602,7 +625,7 @@ def table(args: argparse.Namespace) -> bool:
     return True
 
 
-def main(argv: Optional[List[str]] = None):
+def main(argv: Optional[List[str]] = None) -> None:
     parser = _argument_parser()
     args = parser.parse_args(argv)
     if "func" in args: