def jsonString() {
  def b = new JsonBuilder()
  def jBuild = b {
      type "a"
      kind "b"
  }
  def j = new JsonSlurper().parseText('[{"name":"foo","attributes":[{"type":"x","kind":"x"}]}]')
  json << jBuild
  json = new JsonBuilder(json).toPrettyString()
  echo json
}

[
  {
    "name": "foo",
    "attributes": [
      {
        "type": "x",
        "kind": "x"
      }
    ]
  }
]""";

{
   "type": "a",
   "kind": "b"
}

[
  {
    "name": "foo",
    "attributes": [
      {
        "type": "x",
        "kind": "x"
      },
      {
        "type": "a",
        "kind": "b"
      }
    ]
  }
]

[
  {
    "name": "foo",
    "attributes": [
      {
        "type": "x",
        "kind": "x"
      }
    ]
  },
  {
    "type": "a",
    "kind": "b"
  }
]