func mergeDatasets(ds1, ds2 dataset.Dataset, v string) (dataset.Dataset, error) { return ds1.CommitWithParents(types.String(v), types.NewSet(ds1.HeadRef(), ds2.HeadRef())) }
func addBranchedDataset(newDs, parentDs dataset.Dataset, v string) (dataset.Dataset, error) { return newDs.CommitWithParents(types.String(v), types.NewSet().Insert(parentDs.HeadRef())) }