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 visitdir(self, dir):
        matched = self._matcher.match_recursive(dir)
        if matched is None:
            return True
        elif matched is True:
            return "all"
        else:
            assert matched is False
            return False