public void setPropertyTraversal(final Traversal.Admin<Element, ? extends Property> propertyTraversal) {
        this.propertyTraversal = this.integrateChild(propertyTraversal);
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
@author Daniel Kuppitz (http://gremlin.guru)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/PropertyMapStep.java