def __missing__(self, key):
        if self.default_factory is None:
            raise KeyError(key)
        else:
            ret = self[key] = self.default_factory(name=key)
            return ret
def __init__(self, matchers):
        m1 = matchers[0]
        super(unionmatcher, self).__init__(m1._root, m1._cwd)
        self.traversedir = m1.traversedir
        self._matchers = matchers