When accessing any property of a Board instance that uses the _get_metadata method a TypeError is raised. This is because in _fetch_boards_metadata the function tries to use the Url class' board_list method -- and while it is marked as a staticmethod it still expects the self-argument, which will never be provided by the calling code.
When accessing any property of a Board instance that uses the _get_metadata method a TypeError is raised. This is because in _fetch_boards_metadata the function tries to use the Url class' board_list method -- and while it is marked as a staticmethod it still expects the self-argument, which will never be provided by the calling code.