return NotImplemented

def __gt__(self, other):
    if self.__class__ is other.__class__:
        return self._order > other._order
return NotImplemented

def __le__(self, other):
    if self.__class__ is other.__class__:
        return self._order <= other._order
return NotImplemented

def __lt__(self, other):
    if self.__class__ is other.__class__:
        return self._order < other._order
return NotImplemented
Использовать порядок определения Enum как естественный порядок