code: def paper_link(cls: str) -> Optional[str]:
      cls = importlib.import_module("torch_geometric.nn.conv").__dict__[
          cls
      ]
      match = re.search("<.+?>", inspect.getdoc(cls), flags=re.DOTALL)
      return (
          None
          if match is None
          else match.group().replace("\n", " ")[1:-1]
      )
  
file_path: pytorch_geometric/torch_geometric/nn/conv/utils/cheatsheet.py
imports: import importlib
  import inspect
  import re
  from typing import Optional
label_desc: Use image node_id 2 for calling a global function with example usage: paper_link(cls) and returns: unknown