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):
        r = False
        for m in self._matchers:
            v = m.visitdir(dir)
            if v == "all":
                return v
            r |= v
        return r