code: def test_grad_with_no_arguments_needing_gradients():
      x = C.input_variable(10)
      z = dropout(x, 0.4)
      with pytest.raises(ValueError):
          _, result = z.grad(
              {x: [np.array([5] * 150, "float32").reshape(15, 10)]},
              outputs=[z],
          )
  
file_path: CNTK/bindings/python/cntk/ops/tests/evaluation_test.py
imports: from __future__ import division
  import numpy
  import pytest
  from .ops_test_utils import _test_binary_op, AA, precision, PRECISION_TO_TYPE, unittest_helper
  from cntk import dropout, combine
  import cntk
label_desc: Use image node_id 2 for calling a global function with example usage: test_grad_with_no_arguments_needing_gradients() without return types