json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "title": "VIS.X Adapter Params",
      "description": "A schema which validates params accepted by VIS.X adapter",
      "type": "object",
      "properties": {
          "uid": {
              "type": "integer",
              "description": "An ID which identifies this placement of the impression"
          },
          "size": {
              "type": "array",
              "items": {
                  "type": "integer"
              },
              "minItems": 2,
              "maxItems": 2,
              "description": "An array of two integer containing the dimension"
          }
      },
      "required": [
          "uid"
      ]
  }