@Override
    public boolean hasLabel(final String label) {
        for (final Set<String> set : this.labels) {
            if (set.contains(label))
                return true;
        }
        return false;
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/util/MutablePath.java