def METHOD_NAME(
    initial_bookmarks: t.Union[None, t.Iterable[str], Bookmarks]
) -> None:
    bmm = bookmark_manager(initial_bookmarks=initial_bookmarks)
    expected_bookmarks: t.Set[str]
    if initial_bookmarks is None:
        expected_bookmarks = set()
    elif isinstance(initial_bookmarks, Bookmarks):
        expected_bookmarks = set(initial_bookmarks.raw_values)
    else:
        expected_bookmarks = set(initial_bookmarks)
    assert (sorted(list(bmm.get_bookmarks()))
            == sorted(list(expected_bookmarks)))