code: function Payment() {
      /**
       * The subtotal value
       * @member
       */
      this.subtotal = null;
      /**
       * The total value
       * @member
       */
      this.total = null;
      /**
       * The currency value
       * @member
       */
      this.currency = null;
      /**
       * The source value
       * @member
       */
      this.source = null;
      /**
       * The error of value
       * @member
       * @type { Error }
       */
      this.error = Object.create(Error.prototype);
  
  }
docs: The Payment class
  @constructor
  @alias Payment