code: def get_index_diff_file_names(repo_dir: str) -> Iterable[FileDiff]:
      """
      Return the list of file diff in the staging area (the index)
      """
      repo = Repo(repo_dir)
      for file_diff in repo.head.commit.diff():
          yield FileDiff(
              change_type=file_diff.change_type,
              file_name=file_diff.a_path,
          )
  
file_path: vissl/dev/lint_commit.py
imports: import argparse
  import os
  from typing import Iterable, NamedTuple, Sequence
label_desc: Use image node_id 2 for calling a global function with example usage: get_index_diff_file_names(repo_dir) without return types