code: def walk(path=".", depth=None):
      """
      recursively walk directory to specified depth
      :param path: (str) the base path to start walking from
      :param depth: (None or int) max. recursive depth, None = no limit
      :yields: (str) filename, including path
      """
      if depth and depth == 1:
          for filename in listdir(path):
              yield filename
      else:
          top_pathlen = len(path) + len(os.path.sep)
          for dirpath, dirnames, filenames in os.walk(path):
              dirlevel = dirpath[top_pathlen:].count(os.path.sep)
              if depth and dirlevel >= depth:
                  dirnames[:] = []
              else:
                  for filename in filenames:
                      yield os.path.join(dirpath, filename)
  
imports: import os
  from absl import logging
  import numpy
  import delta.compat
  from tensorflow.python.client import device_lib
  from tensorflow.python.estimator.canned import metric_keys
  from tensorflow.python.util import nest
  from delta.utils.register import registers
label_desc: Use image node_id 15 for calling a global function with example usage: walk(path, depth) without return types