set user-defined limits and apply them

def set_xylims(self, limits, axes=None, side='left'):
        "set user-defined limits and apply them"
        if axes is None:
            axes = self.axes
            if side == 'right':
                axes = self.get_right_axes()
        self.conf.user_limits[axes] = limits
        self.unzoom_all()