code: def _request_loader(self, request: Request) -> Union[User, AnonymousUser]:
          
          header_key = self.token_authentication_header
          args_key = self.token_authentication_key
          token = request.args.get(args_key, request.headers.get(header_key, None))
          if request.is_json:
              data = request.get_json(silent=True) or {}
              token = data.get(args_key, token)
  
          try:
              data = self.remember_token_serializer.loads(token, max_age=self.token_max_age)
              user = self.user_manager.get(data[0])
              if user and self.security_utils_service.verify_hash(data[1], user.password):
                  return user
          except:
              pass
  
          return self.login_manager.anonymous_user()
docs: Attempt to load the user from the request token.