'Simplify a :class:`Complement`.'

@staticmethod
def reduce(A, B):

    if ((B == S.UniversalSet) or A.is_subset(B)):
        return EmptySet()
    if isinstance(B, Union):
        return Intersection((s.complement(A) for s in B.args))
    result = B._complement(A)
    if (result != None):
        return result
    else:
        return Complement(A, B, evaluate=False)
