code: def test_op_negate(operand, device_id, precision):
      t = -1 * AA(operand, dtype=PRECISION_TO_TYPE[precision])
  
      expected_forward = AA([t])
  
      expected_backward = {
          "arg": [
              -1 * np.ones_like(operand, PRECISION_TO_TYPE[precision])
          ]
      }
  
      from cntk import negate
  
      _test_unary_op(
          precision,
          device_id,
          negate,
          operand,
          expected_forward,
          expected_backward,
      )
  
      _test_unary_op(
          precision,
          device_id,
          "-",
          operand,
          expected_forward,
          expected_backward,
      )
  
imports: from __future__ import division
  import numpy
  import pytest
  import cntk
  from .ops_test_utils import unittest_helper, _test_unary_op, _test_binary_op, AA, precision, PRECISION_TO_TYPE, cntk_device
  from cntk.internal import sanitize_dtype_cntk
  from cntk.internal.utils import _ones_like, eval
label_desc: Use image node_id 8 for calling a global function with example usage: test_op_negate(operand, device_id, precision) without return types