ore_event_outside=True``.

    Parameters
    ----------
    ax : `matplotlib.axes.Axes`

    onselect : callable
        A callback function that is called after a release event and the
        selection is created, changed or removed.
        It must have the signature::

            def on_select(min: float, max: float) -> Any

    direction : {"horizontal", "vertical"}
        The direction along which to draw the span selector.

    minspan : float, default: 0
        If selection is less than or equal to *minspan*, the selection is
        removed (when already existing) or cancelled.

    useblit : bool, default: False
        If True, use the backend-dependent blitting features for faster
        canvas updates. See the tutorial :doc:`/tutorials/advanced/blitting`
        for details.

    props : dict, optional
        Dictionary of `matplotlib.patches.Patch` properties.
        Default:

            ``dict(facecolor='red', alpha=0.5)``

    onmove_callback : func(min, max), min/max are floats, default: None
        Called on mouse move while the span is being selected.

    span_stays : bool, default: False
        If True, the span stays visible after the mouse is released.
        Deprecated, use *interactive* instead.

    interactive : bool, default: False
        Whether to draw a set of handles that allow interaction with the
        widget after it is drawn.

    button : `.MouseButton` or list of `.MouseButton`, default: all buttons
        The mouse buttons which activate the span selector.

    handle_props : dict, default: None
        Properties of the handle lines at the edges of the span. Only used
        when *interactive* is True. See `matplotlib.lines.Line2D` for valid
        properties.

    grab_range : float, default: 10
        Distance in pixels within which the interactive tool handles can be
        activated.

    state_modifier_keys : dict, optional
        Keyboard modifiers which affect the widget's behavior.  Values
        amend the defaults, which are:

        - "clear": Clear the current shape, default: "escape".

    drag_from_anywhere : bool, default: False
        If `True`, the widget can be moved by clicking anywhere within
        its bounds.

    ignore_event_outside : bool, default: False
        If `True`, the event triggered outside the span selector will be
        ignored.

    snap_values : 1D array-like, optional
        Snap the selector edges to the given values.

    Examples
    --------
    >>> import matplotlib.pyplot as plt
    >>> import matplotlib.widgets as mwidgets
    >>> fig, ax = plt.subplots()
    >>> ax.plot([1, 2, 3], [10, 50, 100])
    >>> def onselect(vmin, vmax):
    ...     print(vmin, vmax)
    >>> span = mwidgets.SpanSelector(ax, onselect, 'horizontal',
    ...                              props=dict(facecolor='blue', alpha=0.5))
    >>> fig.show()

    See also: :doc:`/gallery/widgets/span_selector`
    r