json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "title": "Registration",
      "description": "Sports activity registration, 12-14 age bracket",
      "type": "object",
      "properties": {
          "name": {
              "type": "string"
          },
          "sex": {
              "allOf": [
                  {
                      "type": "string"
                  },
                  {
                      "enum": [
                          "M",
                          "F"
                      ]
                  }
              ]
          },
          "age": {
              "allOf": [
                  {
                      "type": "integer"
                  },
                  {
                      "minimum": 12
                  },
                  {
                      "maximum": 14
                  }
              ]
          }
      },
      "additionalProperties": false,
      "required": [
          "name",
          "sex",
          "age"
      ]
  }