Define all rich comparison operators in terms of lt

gistfile1.txt

class ComparableMixin:
    def __eq__(self, other):
        return not (self < other or other < self)

    def __le__(self, other):
        return not other < self

class Foo(ComparableMixin):
    def __init__(self, val):
        self.val = val
        
    def __lt__(self, other):
        if not isinstance(other, Foo):
            raise TypeError('Comparing a Foo to a {}'.format(type(other)))
        
        return self.val < other.val

Duh, I'm an idiot, don't inherit from object, just from ComparableMixin only.