How to check for presence in a conversation?

Question

Python

Found the following function:

def check_kf(peer_id:int) -> list:
  authorize.method("messages.getConversationMembers", {
        "peer_id": peer_id
    })["items"]

As I understand it, it allows you to check whether there is a person in the conversation or not. Using it, I tried to create another function:

def add_v_besedy(sender,uid):
  uid = reseived_message[10:19]
  user_id = uid
  if uid in check_kf(3):
    write_message(sender,'text')
  else:
    write_message(sender,'as')

If the user id(int) in the conversation with peer_id = 3, then the send message function is executed.
When I run the code, I get an error on the line ( if uid in check_kf(3): ):
TypeError: argument of type 'NoneType' is not iterable
How can I fix this? I created a function so that if the user, when invited to the conversation, is already in it, some answer is written

Answer 1

To start

in conversation with peer_id = 3

All conversation IDs start at 2000000000, -user id=3Then
, messages.getConversationMembers returns a list of dictionaries in items, so you ca if uid in check_kf(3):n't check through.
https://vk.com/dev/messages.getConversationMembers
And on top of all this, the function check_kfdoes not return anything, so it needs to be completed

def check_kf(peer_id:int) -> list:
  return authorize.method("messages.getConversationMembers", {
        "peer_id": peer_id
    })["items"]

Something like this

def add_v_besedy(sender,uid):
  uid = reseived_message[10:19]
  user_id = uid
  users = check_kf(2000000003)
  for user in users:
    if user['member_id']  == user_id:
      write_message(sender,'text')
      return
  write_message(sender,'as')

Well, there's reseived_message[10:19]clearly something wrong.

Answer 2

In fact, you simply do not return anything from the function, and this is an error, because you cannot check for the presence of a user in the list if this list does not exist

def check_kf(peer_id:int) -> list:
  return authorize.method("messages.getConversationMembers", {
        "peer_id": peer_id
    })["items"]

Answer 3

1) Get a list of participants
2) Check if the required ID is in the list