public void updateEdges(String kmer, int pos, boolean strand, int record, List<SequenceParser.Feature> features){

    if(features == null) {
        features = Arrays.asList();
    }

    g.withSideEffect("features",features)
            .V().has("prefix", kmer.substring(0,kmer.length()-1)).fold().coalesce(__.unfold(),
            __.addV("prefix_node").property("prefix",kmer.substring(0,kmer.length()-1)) ).as("v1").
            coalesce(__.V().has("prefix", kmer.substring(1,kmer.length())),
                    __.addV("prefix_node").property("prefix",kmer.substring(1,kmer.length())) ).as("v2").
            sideEffect(__.choose(__.select("features").unfold().count().is(P.eq(0)),
                    __.addE("suffix_edge").property("record",record).
                            property("strand",strand).property("pos",pos).from("v1").to("v2")).
            select("features").unfold().
            addE("suffix_edge").property("record",record).property("strand",strand).property("pos",pos)
            .property(__.map(t -> ((SequenceParser.Feature)t.get()).category),
                    __.map(t -> ((SequenceParser.Feature)t.get()).feature)).from("v1").to("v2")).
            iterate();

}