docs: def get_actual_start_time(self):
          """Gets the time this assessment was started.
  
          return: (osid.calendaring.DateTime) - the start time
          raise:  IllegalState - ``has_started()`` is ``false``
          *compliance: mandatory -- This method must be implemented.*
  
          """
          if not self.has_started():
              raise errors.IllegalState('this assessment has not yet started')
          if self._my_map['actualStartTime'] is None:
              raise errors.IllegalState('this assessment has not yet been started by the taker')
          else:
              start_time = self._my_map['actualStartTime']
              return DateTime(year=start_time.year,
                              month=start_time.month,
                              day=start_time.day,
                              hour=start_time.hour,
                              minute=start_time.minute,
                              second=start_time.second,
                              microsecond=start_time.microsecond)