class A(object):
    def __lt__(self, rhs):
        print 'A.lt'
        return NotImplemented
    def __gt__(self, rhs):
        print 'A.gt'
        return NotImplemented
    def __cmp__(self, rhs):
        print 'A.cmp'
        return NotImplemented

class B(object):
    def __lt__(self, rhs):
        print 'B.lt'
        return NotImplemented
    def __gt__(self, rhs):
        print 'B.gt'
        return NotImplemented
    def __cmp__(self, rhs):
        print 'B.cmp'
        return NotImplemented

a, b = A(), B()
print a < b
print cmp(a, b)