code: def get_comment_lookup_session(self):
          
          if not self.supports_comment_lookup():
              raise errors.Unimplemented()
          # pylint: disable=no-member
          return sessions.CommentLookupSession(runtime=self._runtime)
docs: Gets the ``OsidSession`` associated with the comment lookup service.
  
          return: (osid.commenting.CommentLookupSession) - a
                  ``CommentLookupSession``
          raise:  OperationFailed - unable to complete request
          raise:  Unimplemented - ``supports_comment_lookup()`` is
                  ``false``
          *compliance: optional -- This method must be implemented if
          ``supports_comment_lookup()`` is ``true``.*