'Need to overload so that twinx/twiny will work with
these axes.'

def _make_twin_axes(self, *kl, **kwargs):

    ax2 = type(self)(self.figure, self.get_position(True), *kl, **kwargs)
    ax2.set_axes_locator(self.get_axes_locator())
    self.figure.add_axes(ax2)
    return ax2
