How to make the bot only respond to messages?

Question

In contact with

The bot joins the conference, and works as an auto-responder, replying to messages. While joining someone, the bot stalls because it is responding to a message by id. The question is, make the bot ignore the introduction by link/kick/invitation/change data of the conversation

vk_api.exceptions.ApiError: [100] One of the parameters specified was missing or invalid: cannot reply this message

Answer 1

To be honest, I do not know if this method is correct or not, but it works

for event in longpoll.listen():
    if event.type == VkEventType.MESSAGE_NEW:
        if 'source_act' not in event.extra_values:
            print(event.extra_values)

source_act contains an action, which is exactly what is needed. In ordinary messages - it is not there, just check its absence and that's it !!!
If you have other solutions to the problem, please suggest