the code in `RedisModel` `validate_primary_key` wrongly assumes there are multiple primary keys: ```python if getattr(field_info, "primary_key", None): primary_keys += 1 ``` should really be: ```python if getattr(field_info, "primary_key", None) is True: primary_keys += 1 ``` because I'm getting `PydanticUndefined` sometimes instead of None