code: def login_required(view_function):
      
      @wraps(view_function)    # Tells debuggers that is is a function wrapper
      def decorator(*args, **kwargs):
          user_manager = current_app.user_manager
          
          # User must be logged in with a confirmed email address
          allowed = _is_logged_in_with_confirmed_email(user_manager)
          if not allowed:
              # Redirect to unauthenticated page
              return user_manager.unauthenticated_view()
  
          # It's OK to call the view
          return view_function(*args, **kwargs)
  
      return decorator
docs: This decorator ensures that the current user is logged in.
  
      Example::
  
          @route('/member_page')
          @login_required
          def member_page():  # User must be logged in
              ...
  
      If USER_ENABLE_EMAIL is True and USER_ENABLE_CONFIRM_EMAIL is True,
      this view decorator also ensures that the user has a confirmed email address.
  
      | Calls unauthorized_view() when the user is not logged in
          or when the user has not confirmed their email address.
      | Calls the decorated view otherwise.