def __init__(self, hashes=None):
        # type: (Dict[str, List[str]]) -> None
        """
        :param hashes: A dict of algorithm names pointing to lists of allowed
            hex digests
        """
        self._allowed = {} if hashes is None else hashes

        :param hashes: A dict of algorithm names pointing to lists of allowed
            hex digests
        
product/gradle-plugin/src/main/python/pip/_internal/utils/hashes.py