public default void removeLocalChild(final Traversal.Admin<?, ?> localChildTraversal) {
        throw new IllegalStateException("This traversal parent does not support the removal of local traversals: " + this.getClass().getCanonicalName());
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/TraversalParent.java