code: def get_repositories_by_composition(self, composition_id):
          
          # Implemented from template for
          # osid.resource.ResourceBinSession.get_bins_by_resource
          mgr = self._get_provider_manager('REPOSITORY', local=True)
          lookup_session = mgr.get_repository_lookup_session(proxy=self._proxy)
          return lookup_session.get_repositories_by_ids(
              self.get_repository_ids_by_composition(composition_id))
docs: Gets the ``Repository`` objects mapped to a ``Composition``.
  
          arg:    composition_id (osid.id.Id): ``Id`` of a ``Composition``
          return: (osid.repository.RepositoryList) - list of repositories
          raise:  NotFound - ``composition_id`` is not found
          raise:  NullArgument - ``composition_id`` is ``null``
          raise:  OperationFailed - unable to complete request
          raise:  PermissionDenied - authorization failure
          *compliance: mandatory -- This method must be implemented.*