public List<Traversal.Admin<S, S>> getGlobalChildren() {
        return null == this.repeatTraversal ? Collections.emptyList() : Collections.singletonList(this.repeatTraversal);
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/branch/RepeatStep.java