code: def _initialise_action_states(self):
          
          self.action_enable_monitoring.setChecked(self.app.service.is_running())
          self.action_enable_monitoring.setEnabled(not self.app.serviceDisabled)
docs: Some menu actions have on/off states that have to be initialised. Perform all non-trivial action state
          initialisations.
          Trivial ones (i.e. setting to some constant) are done in the Qt UI file,
          so only perform those that require some run-time state or configuration value here.