json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "type": "object",
      "title": "Newsletter Subscription",
      "properties": {
          "name": {
              "type": "string",
              "minLength": 8,
              "maxLength": 80,
              "attrs": {
                  "placeholder": "Full Name",
                  "title": "Please enter your full name"
              }
          },
          "email": {
              "type": "string",
              "maxLength": 120,
              "attrs": {
                  "type": "email",
                  "placeholder": "Email"
              }
          },
          "lists": {
              "type": "string",
              "enum": [
                  "Daily New",
                  "Promotion"
              ]
          }
      },
      "additionalProperties": false,
      "required": [
          "name",
          "email",
          "lists"
      ]
  }