code: def _calc_dir_size(path):
      
      dir_size = 0
      for (root, dirs, files) in os.walk(path):
          for fn in files:
              full_fn = os.path.join(root, fn)
              dir_size += os.path.getsize(full_fn)
  
      return dir_size
docs: Calculate size of all files in `path`.
  
      Args:
          path (str): Path to the directory.
  
      Returns:
          int: Size of the directory in bytes.