anchor.diff:     "_index": "test",
      "_type": "_doc",
      "_id": "1",
  -   "_version": 6,
  +   "_version": 7,
      "result": "noop"
   }
   --------------------------------------------------
  
positive.code: // TEST[continued]
  
  We can add a tag to the list of tags (note, if the tag exists, it
  will still add it, since its a list):
  
  [source,js]
  --------------------------------------------------
  
negative.code: {
      "script" : {
          "source": "ctx._source.tags.add(params.tag)",
          "lang": "painless",
          "params" : {
              "tag" : "blue"
          }
      }
  }
  --------------------------------------------------
  // CONSOLE
  // TEST[continued]
  
  We can remove a tag from the list of tags. Note that the Painless function to
  `remove` a tag takes as its parameter the array index of the element you wish
  to remove, so you need a bit more logic to locate it while avoiding a runtime
  error. Note that if the tag was present more than once in the list, this will
  remove only one occurrence of it:
  
  [source,js]
  --------------------------------------------------
  POST test/_doc/1/_update
  {
      "script" : {
          "source": "if (ctx._source.tags.contains(params.tag)) { ctx._source.tags.remove(ctx._source.tags.indexOf(params.tag)) }",
          "lang": "painless",
          "params" : {
              "tag" : "blue"
  