so, hypothetically, if UserA granted GoogleGroupB "Admin" access to WidgetC, it might look like

go
            Tuple: &pb.RelationTuple{
                User: &pb.User{UserOneof: &pb.User_Userset{Userset: &pb.ObjectAndRelation{
                    Namespace: "user",
                    ObjectId:  "googlegroupB@googlegroups.com",
                    Relation:  "...",
                }}},
                ObjectAndRelation: &pb.ObjectAndRelation{
                    Namespace: "widget",
                    ObjectId:  "widgetC",
                    Relation:  "admin",
                },
            },