and labels on or off. If a string,
            possible values are:

            ======== ==========================================================
            Value    Description
            ======== ==========================================================
            'on'     Turn on axis lines and labels. Same as ``True``.
            'off'    Turn off axis lines and labels. Same as ``False``.
            'equal'  Set equal scaling (i.e., make circles circular) by
                     changing axis limits. This is the same as
                     ``ax.set_aspect('equal', adjustable='datalim')``.
                     Explicit data limits may not be respected in this case.
            'scaled' Set equal scaling (i.e., make circles circular) by
                     changing dimensions of the plot box. This is the same as
                     ``ax.set_aspect('equal', adjustable='box', anchor='C')``.
                     Additionally, further autoscaling will be disabled.
            'tight'  Set limits just large enough to show all data, then
                     disable further autoscaling.
            'auto'   Automatic scaling (fill plot box with data).
            'image'  'scaled' with axis limits equal to data limits.
            'square' Square plot; similar to 'scaled', but initially forcing
                     ``xmax-xmin == ymax-ymin``.
            ======== ==========================================================

        emit : bool, default: True
            Whether observers are notified of the axis limit change.
            This option is passed on to `~.Axes.set_xlim` and
            `~.Axes.set_ylim`.

        Returns
        -------
        xmin, xmax, ymin, ymax : float
            The axis limits.

        See Also
        --------
        matplotlib.axes.Axes.set_xlim
        matplotlib.axes.Axes.set_ylim
        T