code: def _gen_ckpt_fn_def(label, free_vars: List[str]) -> str:
      """
      Generate the checkpoint function definition
      """
      return (
          f"def checkpoint_{label}({', '.join(['self'] + free_vars)}):"
      )
  
file_path: ColossalAI/colossalai/fx/codegen/activation_checkpoint_codegen.py
imports: from typing import Any, Dict, Iterable, List, Tuple
  import torch
  import colossalai
label_desc: Use image node_id 7 for calling a global function with example usage: _gen_ckpt_fn_def(label, free_vars) and returns: str, label, str, str, str