code: def testSum(self):
      self._Test(
          partial(_NcclReduce, nccl_ops.reduce_sum), lambda x, y: x + y
      )
  
imports: from functools import partial
  import numpy
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gradients
  from tensorflow.python.ops import nccl_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 1 for calling the SingleReduceTest obj's underlying member method code with example usage: obj.testSum() without return types