def METHOD_NAME(funcname):
    """What happens when no region has been supplied?"""
    s = AstroSession()
    # This is a bit awkward as we have to send a region to
    # DS9 with XPA so we can check we can read it back
    # with notice2d_image.
    #
    d = example_data()
    s.set_data(d)
    s.image_data()
    func = getattr(s, f"{funcname}2d_image")
    with pytest.raises(ValueError,
                       match="^unable to parse region string: ''$"):
        func()