code: def _is_rank_zero(self, runner):
      invalidInputError(
          runner, "Sanity check failed. Runner must not be None!"
      )
      rank = runner.rank
      return rank == 0
  
file_path: BigDL/python/orca/src/bigdl/orca/learn/pytorch/callbacks/wandb.py
imports: from bigdl.orca.learn.pytorch.callbacks import Callback
  from bigdl.dllib.utils.log4Error import invalidInputError
  import copy
label_desc: Use image node_id 5 for calling the WandbLoggerCallback obj's underlying member method code with example usage: obj._is_rank_zero(runner) and returns: unknown