{
  "@context": "http://www.w3.org/ns/shex.jsonld",
  "type": "Schema",
  "shapes": [
    { "type": "ShapeDecl",
    "id": "http://a.example/vs1",
    "shapeExpr": {
      "type": "NodeConstraint",
      "values": [
        "http://a.example/v1",
        "http://a.example/v2",
        "http://a.example/v3"
      ]
    } }
  ]
}