python comparable mixin to ease comparision and hashing of objects

comparable_mixin.py

class ComparableMixin(object):
    def _compare(self, other, method):
        try:
            return method(self._cmpkey(), other._cmpkey())
        except (AttributeError, TypeError):
            raise NotImplementedError("_cmpkey not implemented")

    def __lt__(self, other):
        return self._compare(other, lambda s,o: s < o)

    def __le__(self, other):
        return self._compare(other, lambda s,o: s <= o)

    def __eq__(self, other):
        return self._compare(other, lambda s,o: s == o)

    def __ge__(self, other):
        return self._compare(other, lambda s,o: s >= o)

    def __gt__(self, other):
        return self._compare(other, lambda s,o: s > o)

    def __ne__(self, other):
        return self._compare(other, lambda s,o: s != o)

    def __hash__(self):
        try:
            return hash(self._cmpkey())
        except (AttributeError, TypeError):
            raise NotImplementedError("_cmpkey not implemented")