has_parameter() in callback throws exception

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I am not sure how this is supposed to be done:

I have a parameter client and the node which is passed to the client spins ...

rclcpp::spin( paramServer.get_node_base_interface() );

Now when I get a service callback, and I call the function has_parameter():

paramClient.has_parameter( paramName )

I get the exception Node has already been added to an executor because inside has_parameter() it does spin_node_until_future_complete.

Only solution I can think of is to do it like that:

rclcpp::WallRate rate(5);
  while( rclcpp::ok() )
  {
     rclcpp::spin_some( paramServer.get_node_base_interface() );
     rate.sleep();
  }

So is it correct that I am not allowed to just spin the node if I want to do such things inside a subclassed node ( class ParamServer : public rclcpp::Node )?