@Override
    public int hashCode() {
        int result = super.hashCode();
        if (this.dedupTraversal != null)
            result ^= this.dedupTraversal.hashCode();
        if (this.dedupLabels != null)
            result ^= this.dedupLabels.hashCode();
        return result;
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/filter/DedupGlobalStep.java