Get information about document references.

    Helper for :meth:`~.firestore_v1beta1.client.Client.get_all`.

    Args:
        references (List[.DocumentReference, ...]): Iterable of document
            references.

    Returns:
        Tuple[List[str, ...], Dict[str, .DocumentReference]]: A two-tuple of

        * fully-qualified documents paths for each reference in ``references``
        * a mapping from the paths to the original reference. (If multiple
          ``references`` contains multiple references to the same document,
          that key will be overwritten in the result.)

def _reference_info(references):
    """Get information about document references.

    Helper for :meth:`~.firestore_v1beta1.client.Client.get_all`.

    Args:
        references (List[.DocumentReference, ...]): Iterable of document
            references.

    Returns:
        Tuple[List[str, ...], Dict[str, .DocumentReference]]: A two-tuple of

        * fully-qualified documents paths for each reference in ``references``
        * a mapping from the paths to the original reference. (If multiple
          ``references`` contains multiple references to the same document,
          that key will be overwritten in the result.)
    """
    document_paths = []
    reference_map = {}
    for reference in references:
        doc_path = reference._document_path
        document_paths.append(doc_path)
        reference_map[doc_path] = reference

    return document_paths, reference_map