docs: def get_composition_id(self):
          """Gets the ``Composition``  ``Id`` corresponding to this asset.
  
          return: (osid.id.Id) - the composiiton ``Id``
          raise:  IllegalState - ``is_composition()`` is ``false``
          *compliance: mandatory -- This method must be implemented.*
  
          """
          # Implemented from template for osid.learning.Activity.get_objective_id
          if not bool(self._my_map['compositionId']):
              raise errors.IllegalState('composition empty')
          return Id(self._my_map['compositionId'])