json_schema: {
      "properties": {
          "attributes": {
              "properties": {
                  "integer": {
                      "title": "integer",
                      "type": "integer"
                  },
                  "string": {
                      "items": {
                          "type": "string"
                      },
                      "minItems": 1,
                      "title": "string",
                      "type": "array"
                  }
              },
              "title": "feature attributes",
              "type": "object"
          }
      },
      "title": "DataType2",
      "type": "object"
  }