def task_list_item_list_description(data, singular, plural):
    """
    Returns a description for a task list item depending on how many
    items are in its contents
    """
    if len(data) == 0:
        return None
    elif len(data) == 1:
        return f"1 {singular} added"
    else:
        return f"{len(data)} {plural} added"