class_docstr: Test all-reduce vs. single-reduce plus broadcast in one session.run.
class_docstr_tok: ["Test","all-reduce","vs.","single-reduce","plus","broadcast","in","one","session.run","."]
code: def _Combined(self, tensors, devices):
      all_reduce_tensors = _NcclAllReduce(
          nccl_ops.all_sum, tensors, devices
      )
      single_reduce_tensors = _NcclReduce(
          nccl_ops.reduce_sum, tensors, devices
      )
      broadcast_tensors = _NcclBroadcast(single_reduce_tensors, devices)
      return all_reduce_tensors + broadcast_tensors
  
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 CombinedTest obj's underlying member method code with example usage: obj._Combined(tensors, devices) and returns: unknown