def test_remove(self):
        prio_set_list = event._PrioritizedSetList()
        obj = (1,)

        prio_set_list.add(1, obj)
        assert prio_set_list
        prio_set_list.remove(obj)
        assert not prio_set_list

        with pytest.raises(ValueError) as excinfo:
            prio_set_list.remove(obj)
        excinfo.match(r"can not be found")
def _create_3d_axis():
    """creates a subplot with 3d projection if one does not already exist"""
    from matplotlib.projections import get_projection_class
    from matplotlib import _pylab_helpers

    create_axis = True
    if _pylab_helpers.Gcf.get_active() is not None:
        if isinstance(plt.gca(), get_projection_class('3d')):
            create_axis = False
    if create_axis:
        plt.figure()
        plt.subplot(111, projection='3d')