def METHOD_NAME():
    """
    The class should initialize with a list of length 3.
    The class should raise an exception if the length of
    points is not 3.
    """
    vec3 = Vec3([1, 2, 3])
    assert vec3.x1 == 1.0
    assert vec3.x2 == 2.0
    assert vec3.x3 == 3.0
    with pytest.raises(Exception):
        vec3 = Vec3([1, 2, 3, 4])
    with pytest.raises(Exception):
        vec3 = Vec3([1, 2])