public boolean filter(final Traverser.Admin<S> traverser) {
        return this.allowClasses == this.classFilter.isInstance(traverser.get());
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/filter/ClassFilterStep.java