def ShowDag(self, nodes, ctx):
        dlg = DAGViewerOptions(self)
        res = dlg.ShowModal()
        if res is wx.ID_OK:
            return

        self.GetStatusBar().SetStatusText("Rendering Graph...")
        if not self._dag_viewer:
            self.CreateDAGViewer()

        try:
            self._dag_viewer.SetNodes(nodes,
                                      ctx,
                                      max_depth=dlg.max_depth,
                                      layout_style=dlg.layout_style)
            self._mgr.Update()
            self.GetStatusBar().SetStatusText("Ready")
        except Exception, e:
            traceback.print_tb(sys.exc_traceback)
            self._dag_viewer.Close()
            msg = wx.MessageDialog(self, str(e), "An error occurred",  wx.OK | wx.ICON_ERROR)
            msg.ShowModal()
            msg.Destroy()
            self.GetStatusBar().SetStatusText("An error occurred: %s" % e)
            raise
dataset/ETHPy150Open manahl/mdf/mdf/viewer/frame.py/MDFViewerFrame.ShowDag/operator `!=` -> `is`