def METHOD_NAME(self, directory: str) -> list[str]:
    """Return a list directory paths found directly under the given directory."""
    parts = directory.rstrip(os.path.sep).split(os.path.sep)
    item = get_tree_item(self.__files_tree, parts)
    return [os.path.join(directory, key) for key in item[0].keys()] if item else []