def METHOD_NAME(self, atom):
    known_pos = np.array([3.94543672, -12.4060812, -7.26820087], dtype=np.float32)
    a = atom
    # new position property (mutable)
    assert_almost_equal(a.position, known_pos)
    pos = a.position + 3.14
    a.position = pos
    assert_almost_equal(a.position, pos)