def _model_execute(self, server):
        server.exception = None
        if server.queue is None:
            try:
                self.run_iteration(server.case.uuid)
            except Exception as exc:
                server.exception = sys.exc_info()
                self._logger.critical('Caught exception: %r' % exc)
        else:
            server.queue.put((self._remote_model_execute, server))
Delete an existing dag node and its edges, and make sure the QGraphicsScene cleans up as well.
dataset/ETHPy150Open OpenMDAO/OpenMDAO-Framework/openmdao.lib/src/openmdao/lib/drivers/caseiterdriver.py/CaseIteratorDriver._model_execute--crossover with--dataset/ETHPy150Open andrew-gardner/dependsworkflow/depends/depends_main_window.py/MainWindow.deleteNodes