def METHOD_NAME(self):
    """Test :func:`colour.models.rgb.prismatic.RGB_to_Prismatic` definition."""
    np.testing.assert_array_almost_equal(
        RGB_to_Prismatic(np.array([0.0, 0.0, 0.0])),
        np.array([0.0, 0.0, 0.0, 0.0]),
        decimal=7,
    )
    np.testing.assert_array_almost_equal(
        RGB_to_Prismatic(np.array([0.25, 0.50, 0.75])),
        np.array([0.7500000, 0.1666667, 0.3333333, 0.5000000]),
        decimal=7,
    )