declare const Blitz: {
  init: (key: string) => boolean;
  createUser: (userId: string) => boolean;
  setUserName: (userName: string) => boolean;
  setUserEmail: (userEmail: string) => boolean;
  setUserAttribute: (filter: string, filter_value: string, date_type: string) => boolean;
  setUserProperties: (properties: any) => boolean;
  setSurveyLanguage: (lang: string) => boolean;
  setSurveyTheme: (theme: string) => boolean;
  subscribeEvent: (event_name: string, callback_fn: Function) => boolean;
  triggerEvent: (trigger: string, properties?: Object) => boolean;
  logout: () => boolean;
};
export default Blitz;