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 _prefix(kindpats):
    """Whether all the patterns match a prefix (i.e. recursively)"""
    for kind, pat, source in kindpats:
        if kind not in ("path", "relpath"):
            return False
    return True