def METHOD_NAME(self):
    x = SpatialVelocity.Empty()
    self.assertEqual(len(x), 0)
    x.append(SpatialVelocity([1, 2, 3, 4, 5, 6]))
    self.assertEqual(len(x), 1)
    x.append(SpatialVelocity([7, 8, 9, 10, 11, 12]))
    self.assertEqual(len(x), 2)
    y = x[0]
    self.assertIsInstance(y, SpatialVelocity)
    self.assertEqual(len(y), 1)
    self.assertTrue(all(y.A == np.r_[1, 2, 3, 4, 5, 6]))
    y = x[1]
    self.assertIsInstance(y, SpatialVelocity)
    self.assertEqual(len(y), 1)
    self.assertTrue(all(y.A == np.r_[7, 8, 9, 10, 11, 12]))
    x.insert(0, SpatialVelocity([20, 21, 22, 23, 24, 25]))
    y = x[0]
    self.assertIsInstance(y, SpatialVelocity)
    self.assertEqual(len(y), 1)
    self.assertTrue(all(y.A == np.r_[20, 21, 22, 23, 24, 25]))
    y = x[1]
    self.assertIsInstance(y, SpatialVelocity)
    self.assertEqual(len(y), 1)
    self.assertTrue(all(y.A == np.r_[1, 2, 3, 4, 5, 6]))