code: def cross_replica_mean(t, num_shards_per_group=None):
      """Calculates the average value of input tensor across TPU replicas."""
      num_shards = tpu_function.get_tpu_context().number_of_shards
      if not num_shards_per_group:
          return tf1.tpu.cross_replica_sum(t) / tf.cast(
              num_shards, t.dtype
          )
  
      group_assignment = None
      if num_shards_per_group > 1:
          if num_shards % num_shards_per_group != 0:
              raise ValueError(
                  "num_shards: %d mod shards_per_group: %d, should be 0"
                  % (num_shards, num_shards_per_group)
              )
          num_groups = num_shards // num_shards_per_group
          group_assignment = [
              [
                  x
                  for x in range(num_shards)
                  if x // num_shards_per_group == y
              ]
              for y in range(num_groups)
          ]
      return tf1.tpu.cross_replica_sum(t, group_assignment) / tf.cast(
          num_shards_per_group, t.dtype
      )
  
imports: from typing import Text, Tuple, Union
  import tensorflow
  import argparse
  import tensorflow.compat.v1
  from enum import Enum
  from collections import namedtuple
  from tensorflow.python.eager import tape
  from tensorflow.python.tpu import tpu_function
label_desc: Use image node_id 6 for calling a global function with example usage: cross_replica_mean(t, num_shards_per_group) and returns: unknown, unknown