@Override
        public <V> Iterator<V> values(final String... propertyKeys) {
            return IteratorUtils.map(this.<V>properties(propertyKeys), property -> property.value());
        }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/computer/util/ComputerGraph.java