def __new__(cls, response, parser=etree.HTMLParser):
        cache = cls.cache.setdefault(response, {})
        if cache not in parser:
            obj = object_ref.__new__(cls)
            cache[parser] = _factory(response, parser)
        return cache[parser]
dataset/ETHPy150Open wcong/ants/ants/selector/lxmldocument.py/LxmlDocument.__new__/swapped operands of `not in`