@SuppressWarnings({"CloneDoesntDeclareCloneNotSupportedException", "CloneDoesntCallSuperClone"})
    @Override
    public VertexProgram<Tuple> clone() {
        return this;
    }
@author Daniel Kuppitz (http://gremlin.guru)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/computer/clone/CloneVertexProgram.java