def METHOD_NAME(variant_scalar_rgb):
    from mitsuba import spline
    nodes_x = Float([0.0, 0.25, 0.5, 0.75, 1.0])
    nodes_y = Float([0.0, 0.25, 0.5, 0.75, 1.0])
    values = Float([0.0, 0.25, 0.5, 0.75, 1.0,
                       0.0, 0.25, 0.5, 0.75, 1.0,
                       0.0, 0.25, 0.5, 0.75, 1.0,
                       0.0, 0.25, 0.5, 0.75, 1.0,
                       0.0, 0.25, 0.5, 0.75, 1.0])
    assert dr.allclose(spline.eval_2d(nodes_x, nodes_y, values, 0, 0),     0)
    assert dr.allclose(spline.eval_2d(nodes_x, nodes_y, values, 1, 0),     1)
    assert dr.allclose(spline.eval_2d(nodes_x, nodes_y, values, 0, 1),     0)
    assert dr.allclose(spline.eval_2d(nodes_x, nodes_y, values, 1, 1),     1)
    assert dr.allclose(spline.eval_2d(nodes_x, nodes_y, values, 0.5, 0.5), 0.5)