public TinkerProperty copy(final Element newOwner) {
        return new TinkerProperty(newOwner, key, value);
    }
The existence of this object implies the property is present, thus even a {@code null} value means "present".
tinkergraph-gremlin/src/main/java/org/apache/tinkerpop/gremlin/tinkergraph/structure/TinkerProperty.java