def save_figure(self, *args):
        filetypes = self.canvas.get_supported_filetypes_grouped()
        sorted_filetypes = sorted(filetypes.items())
        default_filetype = self.canvas.get_default_filetype()

        startpath = os.path.expanduser(mpl.rcParams['savefig.directory'])
        start = os.path.join(startpath, self.canvas.get_default_filename())
        filters = []
        selectedFilter = None
        for name, exts in sorted_filetypes:
            exts_list = " ".join(['*.%s' % ext for ext in exts])
            filter = f'{name} ({exts_list})'
            if default_filetype in exts:
                selectedFilter = filter
            filters.append(filter)
        filters = ';;'.join(filters)

        fname, filter = QtWidgets.QFileDialog.getSaveFileName(
            self.canvas.parent(), "Choose a filename to save to", start,
            filters, selectedFilter)
        if fname:
            # Save dir for next time, unless empty str (i.e., use cwd).
            if startpath != "":
                mpl.rcParams['savefig.directory'] = os.path.dirname(fname)
            try:
                self.canvas.figure.savefig(fname)
            except Exception as e:
                QtWidgets.QMessageBox.critical(
                    self, "Error saving file", str(e),
                    QtWidgets.QMessageBox.StandardButton.Ok,
                    QtWidgets.QMessageBox.StandardButton.NoButton)
        return fname