Place single `distribution` items into lists

[iannesbitt]

Normalization should include listifying singular distribution items to simplify downstream queries. This could also apply to other list types including creators.

  "distribution": {
    "@type": "DataDownload",
    "contentUrl": "https://ipt.env.duke.edu/archive.do?r=zd_1762",
    "encodingFormat": "application/zip"
  },

should become

  "distribution": [{
    "@type": "DataDownload",
    "contentUrl": "https://ipt.env.duke.edu/archive.do?r=zd_1762",
    "encodingFormat": "application/zip"
  }],

[iannesbitt]

From Dave on slack:

jsonld framing should do the job. For example, this frame will make distribution always an array:

{
  "@context": {
    "@vocab":"http://schema.org/",
    "distribution": {
      "@id":"distribution",
      "@container":"@set"
	}
  },
  "@type":"Dataset"
}

[iannesbitt]

I think these lines:

sonormal/sonormal/__init__.py

Lines 71 to 76 in 8f0137a

	SO_DATASET_FRAME = {
	"@context": "http://schema.org/",
	"@type": "Dataset",
	"identifier": {},
	"creator": {}
	}

Need to change to this:

SO_DATASET_FRAME = {
    "@context": {
      "@vocab":"http://schema.org/",
      "distribution": {
        "@id":"distribution",
        "@container":"@set"
	}
    },
    "@type": "Dataset",
    "identifier": {},
    "creator": {}
}