message: Fix issue in python3
diff: @@ -229,7 +229,7 @@ class ReluTest(test.TestCase):
  return tape.gradient(y, x)
  x = np.asarray([[],[]], dtype=np.float32)
  - z = gradient_checker_v2.compute_gradient(f, [x])[0][0]
  + z = list(gradient_checker_v2.compute_gradient(f, [x]))[0][0]
  self.assertAllEqual(z, np.reshape(x, (0, 0)))
  class Relu6Test(test.TestCase):
  