code: def _cross_replica_sum_grad(op, grad):
      # The gradient of a cross replica sum is also a cross-replica sum.
      # The gradient with respect to group_assignment is None.
      return [gen_tpu_ops.cross_replica_sum(grad, op.inputs[1]), None]
  
imports: from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gen_tpu_ops
  from tensorflow.python.ops.gen_tpu_ops import *
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.tpu import tpu_function
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 7 for calling a global function with example usage: _cross_replica_sum_grad(op, grad) and returns: list