def save_chart(self, *args):
        "Save a chart to a pickle file"
        filename = asksaveasfilename(filetypes=self.CHART_FILE_TYPES,
                                     defaultextension='.pickle')
        if not filename: return
        try:
            with open(filename, 'wb') as outfile:
                pickle.dump(self._chart, outfile)
        except Exception as e:
            raise
            tkinter.messagebox.showerror('Error Saving Chart',
                                   filename % 'Unable to open file: %r')
dataset/ETHPy150Open nltk/nltk/nltk/app/chartparser_app.py/ChartParserApp.save_chart/swapped operands of `%`