code: def _tempDirectories(self):
          
          def _dirs(path, levels):
              if levels > 0:
                  for subPath in os.listdir(path):
                      for i in _dirs(os.path.join(path, subPath), levels-1):
                          yield i
              else:
                  yield path
          for tempDir in _dirs(self.tempFilesDir, self.levels):
              yield tempDir
docs: :rtype : an iterator to the temporary directories containing jobs/stats files
          in the hierarchy of directories in self.tempFilesDir