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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _qt_export_vtkjs(self, show=True):
 """ Spawn an save file dialog to export a vtkjs file. """

        return FileDialog(self.app_window,
                          filefilter=['VTK JS File(*.vtkjs)'],
                          show=show,
                          directory=os.getcwd(),
                          callback=self.export_vtkjs)