code: def start_time(self):
          
  
          timestamp = self.abs_time / 10 ** 9
          if self.time_flags & v4c.FLAG_HD_LOCAL_TIME:
              timestamp = datetime.fromtimestamp(timestamp)
          else:
              timestamp = datetime.fromtimestamp(timestamp, timezone.utc)
  
          return timestamp
docs: getter and setter the measurement start timestamp
  
          Returns
          -------
          timestamp : datetime.datetime
              start timestamp