missing 'restrictions' property

[balhoff]

In GO, we are trying to update to the latest obographs in ROBOT. We have been using owltools, which uses an older obographs release. We noticed this change, which currently upsets the ontobio JSON reader:

owltools:

{
      "definedClassId" : "http://purl.obolibrary.org/obo/GO_0101013",
      "genusIds" : [ "http://purl.obolibrary.org/obo/GO_0005248", "http://purl.obolibrary.org/obo/GO_0008381" ],
      "restrictions" : [ ]
}

robot:

{
      "definedClassId" : "http://purl.obolibrary.org/obo/GO_0101013",
      "genusIds" : [ "http://purl.obolibrary.org/obo/GO_0005248", "http://purl.obolibrary.org/obo/GO_0008381" ]
}

owltools outputs an empty restrictions array, but the newer obographs leaves it out. The schema doesn't mark it as optional:

obographs/schema/obographs-schema.json

Line 237 in 6676b10

"restrictions" : {

Does the obographs writer need a fix? Or should the schema be modified?