code: def duration_so_far(self):
          
          if self._start_instant is None:
              return False
          if self._stop_instant is None:
              return int((instant() - self._start_instant) * 1000)
          return False
docs: Return how the duration so far.
  
          :returns: the duration from the time the Interval was started if the
              interval is running, otherwise ``False``.