$ mypy --version
mypy 0.971 (compiled: yes)
$ mypy --install-types --non-interactive bson gridfs tools pymongo
bson/__init__.py:64: error: Unused "type: ignore" comment
    from codecs import utf_8_decode as _utf_8_decode  # type: ignore[attr-defined]
    ^
bson/__init__.py:65: error: Unused "type: ignore" comment
    from codecs import utf_8_encode as _utf_8_encode  # type: ignore[attr-defined]
    ^
bson/__init__.py: note: In function "_make_c_string_check":
bson/__init__.py:624: error: Redundant cast to "bytes"  [redundant-cast]
            return cast(bytes, _utf_8_encode(string)[0]) + b"\x00"
                   ^
bson/__init__.py: note: In function "_make_c_string":
bson/__init__.py:636: error: Redundant cast to "bytes"  [redundant-cast]
            return cast(bytes, _utf_8_encode(string)[0]) + b"\x00"
                   ^
bson/__init__.py: note: In function "_make_name":
bson/__init__.py:644: error: Redundant cast to "bytes"  [redundant-cast]
        return cast(bytes, _utf_8_encode(string)[0]) + b"\x00"
               ^
bson/__init__.py: note: In member "decode" of class "BSON":
bson/__init__.py:1311: error: Incompatible default for argument "codec_options" (default has type "CodecOptions[MutableMapping[str, Any]]", argument
has type "CodecOptions[_DocumentType]")  [assignment]
        def decode(self, codec_options: CodecOptions[_DocumentType] = DEFAULT_CODEC_OPTIONS) -> _DocumentType:  # type: ignore[override]
                                                                      ^
bson/__init__.py:1311: note: Error code "assignment" not covered by "type: ignore" comment
pymongo/pyopenssl_context.py: note: In member "__init__" of class "SSLContext":
pymongo/pyopenssl_context.py:195: error: Argument "data" to "set_ocsp_client_callback" of "Context" has incompatible type "_CallbackData"; expected
"Optional[bytes]"  [arg-type]
            self._ctx.set_ocsp_client_callback(callback=_ocsp_callback, data=self._callback_data)
                                                                             ^
Found 7 errors in 2 files (checked 80 source files)