code: def tracking_branch(self):
      if not self.is_valid():
          return None
  
      if self.is_head_detached:
          return None
  
      return self.repo.active_branch.tracking_branch()
  
file_path: streamlit/lib/streamlit/git_util.py
imports: import os
  import re
  from typing import Any, Optional, Tuple
  from streamlit import util
label_desc: Use image node_id 4 for calling the GitRepo obj's underlying member method code with example usage: obj.tracking_branch() and returns: self, None, None