@Override
    public CoalesceStep<S, E> clone() {
        final CoalesceStep<S, E> clone = (CoalesceStep<S, E>) super.clone();
        clone.coalesceTraversals = new ArrayList<>();
        for (final Traversal.Admin<S, E> conjunctionTraversal : this.coalesceTraversals) {
            clone.coalesceTraversals.add(conjunctionTraversal.clone());
        }
        return clone;
    }
@author Daniel Kuppitz (http://gremlin.guru)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/CoalesceStep.java