json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "type": "object",
      "properties": {
          "authors": {
              "type": "array",
              "minItems": 1,
              "_uniqueItems": true,
              "items": {
                  "type": "object",
                  "properties": {
                      "name": {
                          "type": "string"
                      },
                      "email": {
                          "type": "string",
                          "format": "email"
                      }
                  },
                  "required": [
                      "name"
                  ]
              }
          },
          "license": {
              "type": "string"
          },
          "title": {
              "type": "string"
          },
          "description": {
              "type": "string"
          }
      }
  }