createEdgePair :: Label -> Id -> Id -> GS (Id, Id)
createEdgePair l snid enid = do (e1, _, _) <- createEdgeRE l snid enid
                                (e2, _, _) <- createEdgeRE l enid snid
                                return (edgeId e1, edgeId e2)
createEdgePair :: Label -> Id -> Id -> GS (Id, Id)
createEdgePair l snid enid = do (e1, _, _) <- createEdgeRE l snid enid
                                (e2, _, _) <- createEdgeRE l enid snid
                                return (edgeId e1, edgeId e2)
createEdgePair l snid enid = do (e1, _, _) <- createEdgeRE l snid enid
                                (e2, _, _) <- createEdgeRE l enid snid
                                return (edgeId e1, edgeId e2)