code: def collate_fn(batch):
      # change the batch data to tensor
      max_len = 0
      for i in batch[1]:
          max_len = max(max_len, len(i))
      return [i for i in batch[0]], torch.tensor(
          [i + [-1] * (max_len - len(i)) for i in batch[1]]
      )
  
file_path: textflint/textflint/input/model/flint_model/flint_model_cws.py
imports: import torch
  from .flint_model import FlintModel, TASK_METRICS
label_desc: Use image node_id 4 for calling the FlintModelCWS obj's underlying member method code with example usage: obj.collate_fn(batch) and returns: unknown,  torch