code: def broadcast_variables(variables, root_rank):
      """Broadcasts variables from root rank to all other processes.
  
      Arguments:
          variables: variables for broadcast
          root_rank: rank of the process from which global variables will be broadcasted
                     to all other processes.
      """
      broadcast_group = _make_broadcast_group_fn()
      return broadcast_group(variables, root_rank)
  
imports: import tensorflow
  from bluefog.tensorflow.mpi_ops import allreduce, broadcast, size
  from bluefog.tensorflow.util import _executing_eagerly, _cache
label_desc: Use image node_id 3 for calling a global function with example usage: broadcast_variables(variables, root_rank) and returns: broadcast_group