SLD4xx - Inheritance

SLD401: Prohibits inheritance from concrete classes.

Allowed base classes:

• Typing: Protocol, Generic

• Exceptions: Exception, BaseException

• Testing: TestCase

• Enums: Enum, IntEnum, StrEnum, Flag, IntFlag

• Other: TypedDict, NamedTuple

# Bad
class MyHandler(BaseHandler):
    ...

# Good
@dataclass(frozen=True, slots=True, kw_only=True)
class MyHandler:
    validator: Validator
    processor: Processor