code: function MonkeyLearnError(error_code, response, message, fileName, lineNumber) {
    let instance = new Error(message, fileName, lineNumber);
    instance.error_code = error_code;
    instance.response = response;
    Object.setPrototypeOf(instance, Object.getPrototypeOf(this));
    if (Error.captureStackTrace) {
      Error.captureStackTrace(instance, MonkeyLearnError);
    }
    return instance;
  }
docs: Custom Error class for MonkeyLearn API errors this is copied from MDN docs: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error