code: def get_objective_id(self):
          
          # Implemented from template for osid.learning.Activity.get_objective_id
          if not bool(self._my_map['objectiveId']):
              raise errors.IllegalState('objective empty')
          return Id(self._my_map['objectiveId'])
docs: Gets the ``Id`` of the related objective.
  
          return: (osid.id.Id) - the objective ``Id``
          *compliance: mandatory -- This method must be implemented.*