code: public void unsubscribe_event(int event_id) throws DevFailed {
          //	Get callback struct for event ID
          EventCallBackStruct callbackStruct =
                  getCallBackStruct(event_callback_map, event_id);
          if (callbackStruct != null) {
              removeCallBackStruct(event_callback_map, callbackStruct);
              unsubscribeTheEvent(callbackStruct);
          }
          else {
              //	If not found check if in failed map
              callbackStruct =
                      getCallBackStruct(failed_event_callback_map, event_id);
              if (callbackStruct != null)
                  removeCallBackStruct(failed_event_callback_map, callbackStruct);
              else
                  Except.throw_event_system_failed("API_EventNotFound",
                          "Failed to unsubscribe event, the event id (" + event_id +
                                  ") specified does not correspond with any known one",
                          "EventConsumer.unsubscribe_event()");
          }
      }
docs: ===============================================================