code: def identity_collate(batch):
      assert isinstance(batch, list) and len(batch) == 1, f"Got {batch}"
      return batch[0]
  
file_path: ReAgent/reagent/evaluation/cb/run_synthetic_bandit.py
imports: import uuid
  from typing import List, Tuple
  import pytorch_lightning
  import torch
  from pytorch_lightning import seed_everything
  from reagent.evaluation.cb.synthetic_contextual_bandit_data import DynamicBanditAgent, DynamicBanditEnv
label_desc: Use image node_id 1 for calling a global function with example usage: identity_collate(batch) and returns: batch