@Override
    default void close() throws Exception {
        for(final Traversal.Admin<?,?> traversal : this.getLocalChildren()) {
            traversal.close();
        }

        for(final Traversal.Admin<?,?> traversal: this.getGlobalChildren()) {
            traversal.close();
        }
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/TraversalParent.java