Random.choice（）照片python-telegram-bot问题

Question

当用户发送带有＆＃34; word＆＃34;的消息时，我需要机器人随机发送照片。但是根据我写的代码，只发送一张照片，而不是随机发送，就像一个单词列表。我不知道怎么做。 这是代码：

from telegram.ext import (Updater, CommandHandler, MessageHandler, Filters,
                          ConversationHandler, BaseFilter)
    import random
    updater = Updater(token="")
    bot=telegram.Bot(token="")
    dispatcher=updater.dispatcher
    photo_list=["/path/path/photo_1.jpg", "/path/path/photo_2.jpg","/path/path/photo_3.jpg")]
    prove=random.choice(photo_list)

    class Filter_photo(BaseFilter):
        def filter(self, message):
            return 'word' in message.text
    filter_a = Filter_photo()
    def word(bot, update):
            bot.send_photo(chat_id=update.message.chat_id, photo=open(prove, "rb")
    a_handler = MessageHandler(filter_a, word)
    dispatcher.add_handler(a_handler)

    updater.start_polling()