Compare multiple cycels on a grid: one subplot per quantity,
        all cycles on the same subplot.

        Args:
            fontsize: Legend fontsize.

def combiplot(self, fontsize=8, **kwargs):
        """
        Compare multiple cycels on a grid: one subplot per quantity,
        all cycles on the same subplot.

        Args:
            fontsize: Legend fontsize.
        """
        ax_list = None
        for i, (label, cycle) in enumerate(self.items()):
            fig = cycle.plot(ax_list=ax_list, label=label, fontsize=fontsize,
                             lw=2.0, marker="o", linestyle="-", show=False)
            ax_list = fig.axes

        return fig