Duration

Hello all, I'm trying to get my head around a problem that involves 
durations and wonder what is the intent behind 
https://schema.org/Duration as a class?

https://schema.org/duration has an expected type of Duration, but I've 
only ever seen examples with text values, e.g.

{
   "@type": "MusicRecording",
   "duration": "PT4M5S"
}

I've never seen

{
   "@type": "MusicRecording",
   "duration": {
      "@type": "Duration",
      "???": "PT4M5S"
    }
}

and I can't get anything like that through the Google testing tool (I 
know, it's not a schema.org testing tool).

Is this

{
   "@type": "MusicRecording",
   "duration": {
      "@type": "Duration",
      "@value": "PT4M5S"
    }
}

valid JSON-LD with Duration as defined as a class rather than a data type?

It would lead us in the direction of a context file with

"minDuration" {
   "@id": "ex:minDuration",
   "@type": "schema:Duration"
}

(FWIW, the issue we have hit with "@type":"xsd:duration" is that the xsd 
spec doesn't mention durations given as weeks (ISO 8601 does) but my 
questions about schema:Duration stand even if it the solution to that.)

Phil

-- 

Phil Barker <http://people.pjjk.net/phil>. http://people.pjjk.net/phil
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