docs: def log_random_sleep(self, minimum=3.0, scale=1.0, hints=None):
          """wrap random sleep.
  
          - log it for debug purpose only
          """
          hints = '{} slept'.format(hints) if hints else 'slept'
          st = time.time()
          helper.random_sleep(minimum, scale)
          log.debug('{} {} {}s'.format(
              self.symbols.get('sleep', ''), hints, self.color_log(time.time() - st)))