@Override
    public DateDiffStep<S> clone() {
        final DateDiffStep<S> clone = (DateDiffStep<S>) super.clone();
        clone.value = this.value;
        clone.dateTraversal = this.dateTraversal;
        return clone;
    }
Reference implementation for date difference step.

@author Valentyn Kahamlyk
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/DateDiffStep.java