def _add_colorbars(self, location='bottom', label_direction=None,   
                       n_ticks=3, decimals=2, fontsize=10, draw_border=True, 
                       outer_labels_only=False, aspect=20, pad=.08, shrink=.3, 
                       fraction=.05, fig=None, ax=None):
            fig = plt if fig is None else fig
            ax = ax if ax is not None else plt.gca()
            cb = fig.colorbar(sm, ticks=ticks, location=location, 
                              fraction=fraction, pad=cbar_pads[i], 
                              shrink=shrink, aspect=aspect, ax=ax)