Can't find where set_stop_run is defined.

[topcoder20022]

There is set_stop_run.container in socket_function(api.py) I can't find where this variable: set_stop_run.container is defined. It occurs an error. Is it a problem of python version? I am using python 3.8 and 3.9 Hope to hear any advices

from flask import Flask, render_template, request, redirect
from threading import Thread
import sqlite3 as sql
import csv
from Helpers.Helpers import server_begin
from SlaveContainer import SlaveContainer
import logging

app = Flask(__name__)

stop_run = False
test_false = True
socket_usage = False


def socket_function(container: SlaveContainer):
    container.start()
    # first_copy
    container.first_copy(container.master.get_open_orders())
    # set variable for stop socket
    set_stop_run.container = container
    global socket_usage
    socket_usage = True


def manual_run():
    container = server_begin()
    t1 = Thread(target=socket_function, args=(container,))
    t1.start()
    return "Processing"


@app.route("/stop", methods=['GET'])
def set_stop_run():
    logger = logging.getLogger('cct')
    global stop_run
    if not stop_run:
        logger.warning('You cannot stop without starting. Think about it :)')
        return redirect("/")
    stop_run = False
    set_stop_run.container.stop()
    logger.info('WebSocket closed')
    return redirect("/", code=302)