aliasing @id not working #174

{
  "@context": {"@vocab": "http://schema.org/", "@base":"http://test", "id":"@id"},
  "id": "id",
  "@type": "Person",
  "name": "Jane Doe",
  "jobTitle": "Professor",
  "telephone": "(425) 123-4567",
  "url": "http://www.janedoe.com"
}

In [33]: jsonld.to_rdf(loads(thedata))
Out[33]: {'@default': []}