code: def get_gradebooks_by_grade_system(self, grade_system_id):
          
          # Implemented from template for
          # osid.resource.ResourceBinSession.get_bins_by_resource
          mgr = self._get_provider_manager('GRADING', local=True)
          lookup_session = mgr.get_gradebook_lookup_session(proxy=self._proxy)
          return lookup_session.get_gradebooks_by_ids(
              self.get_gradebook_ids_by_grade_system(grade_system_id))
docs: Gets the list of ``Gradebooks`` mapped to a ``GradeSystem``.
  
          arg:    grade_system_id (osid.id.Id): ``Id`` of a
                  ``GradeSystem``
          return: (osid.grading.GradebookList) - list of gradebooks
          raise:  NotFound - ``grade_system_id`` is not found
          raise:  NullArgument - ``grade_system_id`` is ``null``
          raise:  OperationFailed - unable to complete request
          raise:  PermissionDenied - authorization failure
          *compliance: mandatory -- This method must be implemented.*