code: def configure_extensions(app):
      
  
      db.init_app(app)
  
      app.wsgi_app = ProxyFix(app.wsgi_app)
  
      assets.init_app(app)
      for asset in bundles:
          for (name, bundle) in asset.iteritems():
              assets.register(name, bundle)
  
      login_manager.login_view = 'frontend.login'
      login_manager.login_message_category = 'info'
  
      @login_manager.user_loader
      def load_user(id):
          return User.query.get(int(id))
  
      login_manager.init_app(app)
  
      cache.init_app(app)
      migrate.init_app(app, db)
      toolbar.init_app(app)
docs: Configure application extensions