def METHOD_NAME(self):
    # just test SpatialVelocity since all types derive from same superclass
    r1 = np.r_[1, 2, 3, 4, 5, 6]
    r2 = np.r_[7, 8, 9, 10, 11, 12]
    a1 = SpatialVelocity(r1)
    a2 = SpatialVelocity(r2)
    self.assertTrue(all((a1 + a2).A == r1 + r2))
    self.assertTrue(all((a1 - a2).A == r1 - r2))
    self.assertTrue(all((-a1).A == -r1))