json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "title": "Server",
      "description": "Server address and port number",
      "type": "object",
      "properties": {
          "server": {
              "type": "object",
              "properties": {
                  "address": {
                      "type": "string"
                  },
                  "port": {
                      "type": "integer"
                  }
              },
              "additionalProperties": false,
              "required": [
                  "address",
                  "port"
              ]
          }
      }
  }