def remove_selection(self, sel):
        """Remove a `Selection`."""
        self._selections.remove(sel)
        # <artist>.figure will be unset so we save them first.
        figures = {artist.figure for artist in [sel.annotation] + sel.extras}
        # ValueError is raised if the artist has already been removed.
        with suppress(ValueError):
            sel.annotation.remove()
        for artist in sel.extras:
            with suppress(ValueError):
                artist.remove()
        for cb in self._callbacks["remove"]:
            cb(sel)
        for figure in figures:
            figure.canvas.draw_idle()
Remove a `Selection`.