Enhancement pattern: sio:Attribute

What skills do I have?

@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix cco:  <http://purl.org/ontology/cco/core#> .

:me 
  a foaf:Person;
  cco:skill <http://dbpedia.org/resource/Java_(programming_language)> .

But, how well do I program Java?

@prefix voag: <http://voag.linkedmodel.org/voag#> .

:me
   sio:has-attribute :java_programming_maturity .

:java_programming_maturity
   a sio:Attribute, cco:skill;
   sio:refers-to <http://dbpedia.org/resource/Java_(programming_language)>;
   voag:hasMaturity <http://dbpedia.org/resource/Wizard_(fantasy)>;
.