@utilities.arguments_not_none<EOL><INDENT>def get_compositions_by_ids(self, composition_ids):<DEDENT>
<EOL>return self._provider_session.get_compositions_by_ids(composition_ids)<EOL>
Gets a ``CompositionList`` corresponding to the given ``IdList``.

        arg:    composition_ids (osid.id.IdList): the list of ``Ids`` to
                retrieve
        return: (osid.repository.CompositionList) - the returned
                ``Composition list``
        raise:  NotFound - an ``Id`` was not found
        raise:  NullArgument - ``composition_ids`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*