code: def recursive_walk(rootdir):
      """
      Yields:
          str: All files in rootdir, recursively.
      """
      for r, dirs, files in os.walk(rootdir):
          for f in files:
              yield os.path.join(r, f)
  
file_path: tensorpack/tensorpack/utils/fs.py
imports: import errno
  import os
  import tqdm
  from six.moves import urllib
  from .None import logger
  from .utils import execute_only_once
label_desc: Use image node_id 3 for calling a global function with example usage: recursive_walk(rootdir) without return types