# Pastebin LDlP3VmS
class FrozenEnum(EnumMeta):
    "prevent creation of new attributes"
    def __getattr__(self, name):
        if name not in self._member_map_:
            raise AttributeError('%s %r has no attribute %r'
                % (self.__class__.__name__, self.__name__, name))
        # mypy does not know this is a metaclass and that __getattr__ is
        # defined in the superclass of the class that uses this
        # so we need to ignore the type error here.
        return super().__getattr__(name)  # type: ignore

    def __setattr__(self, name, value):
        if name in self.__dict__ or name in self._member_map_:
            return super().__setattr__(name, value)
        raise AttributeError('%s %r has no attribute %r'
                % (self.__class__.__name__, self.__name__, name))


class IronicEnum(StrEnum, metaclass=FrozenEnum):
    @classmethod
    def list(cls):
        return list(cls.__members__)