updates the data in already existing plots. the axes objects are provided in axes_list
        Args:
            axes_list: a list of axes objects, this should be implemented in each subscript

        Returns: None

def _update(self, axes_list):
        """
        updates the data in already existing plots. the axes objects are provided in axes_list
        Args:
            axes_list: a list of axes objects, this should be implemented in each subscript

        Returns: None

        """
        plot_type = self.settings['plot_style']
        if plot_type == '2D':
            # we expect exactely one image in the axes object (see ScriptDummy.plot)
            implot = axes_list[1].get_images()[0]
            # now update the data
            implot.set_data(self.data['random data'])

            colorbar = implot.colorbar

            if not colorbar is None:
                colorbar.update_bruteforce(implot)

        else:
            # fall back to default behaviour
            Script._update(self, axes_list)