old_contents: from flask import Flask, render_template, request
  from webui import WebUI
  from threading import Thread
  
  import os
  
  app = Flask(__name__)
  ui = WebUI(app, debug=True)
  
  @app.route('/')
  def main():
    return "Hello world!"
  
  if __name__ == '__main__':
    ui.run()
new_contents: from flask import Flask, render_template, request
  from webui import WebUI
  
  import os
  
  app = Flask(__name__)
  ui = WebUI(app, debug=True)
  
  @app.route('/')
  def main():
    return "Hello world!"
  
  if __name__ == '__main__':
    ui.run()
  
subject: Update test_app.py