Show marker area scale for subplots.

        :param row_column_list: a list containing (row, column) tuples to
            specify the subplots, or None to indicate *all* subplots.
        :param location: the location of the label inside the plot.  May
            be one of 'center', 'upper right', 'lower right', 'upper
            left', 'lower left'.

def set_scalebar_for_all(self, row_column_list=None,
                             location='lower right'):
        """Show marker area scale for subplots.

        :param row_column_list: a list containing (row, column) tuples to
            specify the subplots, or None to indicate *all* subplots.
        :param location: the location of the label inside the plot.  May
            be one of 'center', 'upper right', 'lower right', 'upper
            left', 'lower left'.

        """
        if row_column_list is None:
            for subplot in self.subplots:
                subplot.set_scalebar(location)
        else:
            for row, column in row_column_list:
                subplot = self.get_subplot_at(row, column)
                subplot.set_scalebar(location)