'succeed iff {l1} - {ignore} == {l2} - {ignore}'

def assertListEq(self, l1, l2, ignore):

    missing = ((set(l1) ^ set(l2)) - set(ignore))
    if missing:
        print >>sys.stderr, ('l1=%r\nl2=%r\nignore=%r' % (l1, l2, ignore))
        self.fail(('%r    missing' % missing.pop()))
