json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "title": "DonutChartData",
      "description": "The data contained in a DonutChart",
      "type": "object",
      "properties": {
          "datasets": {
              "type": "array",
              "items": {
                  "type": "object",
                  "properties": {
                      "name": {
                          "type": "string"
                      },
                      "color": {
                          "type": "string",
                          "pattern": "^#[0-9a-fA-F]{6}$"
                      },
                      "value": {
                          "type": "number"
                      }
                  },
                  "required": [
                      "value"
                  ]
              }
          }
      },
      "required": [
          "datasets"
      ]
  }