def METHOD_NAME(self):
    """inplace change of degrees should not be allowed if core spline is
    initialized"""
    z = c.dict_bezier_2p2d()
    r = c.dict_rational_bezier_2p2d()
    b = c.dict_bspline_2p2d()
    n = c.dict_nurbs_2p2d()
    Z, R, B, N = (
        c.splinepy.Bezier,
        c.splinepy.RationalBezier,
        c.splinepy.BSpline,
        c.splinepy.NURBS,
    )
    for props, SClass in zip((z, r, b, n), (Z, R, B, N)):
        # test no core spline
        # this should be fine
        s = SClass()
        s.degrees = props["degrees"]
        s.degrees += 1
        # this shoundn't be fine
        s._new_core(**props)
        with self.assertRaises(ValueError):
            s.degrees += 1