code: def initialize(self, trainer):
      if self.is_master:
          self.snapshot.initialize(trainer)
  
      # If autoload is off, no need to re-init this extension.
      if not self.snapshot.autoload:
          return
  
      if self.snapshot._target is None:
          target = trainer
      else:
          target = self.snapshot._target
  
      # "Broadcast" the target here
      if self.is_master:
          # Find snapshot again
          # TODO(kuenishi): replace with cleaner way to know whether
          # a snapshot is autoloaded or not
          filename = _find_latest_snapshot(
              self.snapshot.filename, trainer.out
          )
          if filename is None:
              data = None
          else:
              buf = io.BytesIO()
              save_npz(buf, target)
              data = buf.getvalue()
  
          for rank in self.replica_set:
              if rank == self.comm.rank:
                  continue
              self.comm.send_obj(data, rank)
  
      # Get the loaded target from master
      else:
          data = self.comm.recv_obj(self.master)
          if data is None:
              return
          load_npz(io.BytesIO(data), target)
  
file_path: chainer/chainermn/extensions/_multi_node_snapshot.py
imports: import io
  from chainer.serializers import load_npz
  from chainer.serializers import save_npz
  from chainer.training.extension import Extension
  from chainer.training.extensions._snapshot import _find_latest_snapshot
label_desc: Use image node_id 3 for calling the _MultiNodeSnapshot obj's underlying member method code with example usage: obj.initialize(trainer) without return types