docs: def init(self, app):
          """
          Initialise from flask app
          This gets configuration values from a flask application.
          :param app: flask.Flask
          :return: boiler.user.user_servce.UserService
          """
          cfg = app.config
          self.welcome_message = cfg.get('USER_SEND_WELCOME_MESSAGE')
          self.require_confirmation = cfg.get(
              'USER_ACCOUNTS_REQUIRE_CONFIRMATION'
          )
  
          subjects = cfg.get('USER_EMAIL_SUBJECTS')
          self.email_subjects = subjects if subjects else dict()
  
          self.jwt_secret = cfg.get('USER_JWT_SECRET')
          self.jwt_algo = cfg.get('USER_JWT_ALGO')
          self.jwt_lifetime = cfg.get('USER_JWT_LIFETIME_SECONDS')
          self.jwt_implementation = cfg.get('USER_JWT_IMPLEMENTATION')
          self.jwt_loader_implementation = cfg.get(
              'USER_JWT_LOADER_IMPLEMENTATION'
          )