code: def is_master(self):
      return self.master == self.comm.rank
  
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 2 for calling the _MultiNodeSnapshot obj's underlying member method code with example usage: obj.is_master() and returns: unknown