def delete_last_bracket(unreadable_json_str) ->str:
    """最後に余計な閉じかっこが存在する場合に削除する"""
    reversed_list = list(reversed(unreadable_json_str))
    for index, char in enumerate(reversed_list):
        if char == '}':
            del reversed_list[index]
            break
    valid_order_list = reversed(reversed_list)
    output = ''.join(valid_order_list)
    return output
