code: def _unbuffered(self, proc, stream='stdout'):
          
          if self.working_handler is not None:
              t = Thread(target=self._handle_process, args=(proc, stream))
              t.start()
          out = getattr(proc, stream)
          try:
              for line in iter(out.readline, ""):
                  yield line.rstrip()
          finally:
              out.close()
docs: Unbuffered output handler.
  
          :type proc: subprocess.Popen
          :type stream: six.text_types
          :return: