code: def _makeNestedTempDir(top, seed, levels=2):
      
      # Valid chars for the creation of temporary directories
      validDirs = hashlib.md5(six.b(str(seed))).hexdigest()
      tempDir = top
      for i in range(max(min(levels, len(validDirs)), 1)):
          tempDir = os.path.join(tempDir, validDirs[i])
          if not os.path.exists(tempDir):
              try:
                  os.makedirs(tempDir)
              except os.error:
                  if not os.path.exists(tempDir):
                      # In the case that a collision occurs and
                      # it is created while we wait then we ignore
                      raise
      return tempDir
docs: Gets a temporary directory in the hierarchy of directories under a given
      top directory.
  
      This exists to avoid placing too many temporary directories under a single
      top in a flat structure, which can slow down metadata updates such as
      deletes on the local file system.
  
      The seed parameter allows for deterministic placement of the created
      directory. The seed is hashed into hex digest and the directory structure
      is created from the initial letters of the digest.
  
      :param top : string, top directory for the hierarchy
      :param seed : string, the hierarchy will be generated from this seed string
      :rtype : string, path to temporary directory - will be created when
          necessary.