code: function HTTPError(statusCode, message) {
      if (!(this instanceof HTTPError)) {
        return new HTTPError(statusCode, message);
      }
  
      assert(statusCode >= 400, 'Not a valid HTTP error code');
  
      this.statusCode = statusCode;
      this.code = statusCode;
      this.message = message || defaultMessage;
    }
docs: Error constructor for creating error objects with a given status code
  @param {Number} statusCode - The HTTP status code
  @param {String} message - The default error message