json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "type": "object",
      "properties": {
          "messages": {
              "type": "array",
              "items": {
                  "type": "object",
                  "properties": {
                      "messageId": {
                          "type": "integer"
                      },
                      "receivedDate": {
                          "type": "integer"
                      },
                      "senderEmail": {
                          "type": "string"
                      },
                      "recipients": {
                          "type": "string"
                      },
                      "subject": {
                          "type": "string"
                      },
                      "hasAttachments": {
                          "type": "boolean"
                      }
                  },
                  "required": [
                      "messageId",
                      "receivedDate",
                      "senderEmail",
                      "recipients",
                      "subject",
                      "hasAttachments"
                  ]
              }
          }
      },
      "required": [
          "messages"
      ]
  }