code: def test_getting_output_from_non_existent_node():
      x = C.input_variable((2,))
      y = C.input_variable((2,))
      x0 = np.asarray([[2.0, 1.0]])
      y0 = np.asarray([[4.0, 6.0]])
  
      sum_node = x + 2
  
      # times_node not having sum_node
      times_node = x * y
  
      with pytest.raises(ValueError):
          sum_output = times_node.forward(
              {x: x0, y: y0}, sum_node.outputs
          )
  
imports: import numpy
  import os
  import pytest
  import cntk
  from .ops_test_utils import compare_lists_of_np_arrays, AA, cntk_device
  from cntk.io import MinibatchSource, CTFDeserializer, StreamDefs, StreamDef
label_desc: Use image node_id 8 for calling a global function with example usage: test_getting_output_from_non_existent_node() without return types