code: def init_app(self, app, env_file=None, verbose_mode=False):
          
          if self.app is None:
              self.app = app
          self.verbose_mode = verbose_mode
  
          if env_file is None:
              env_file = os.path.join(os.getcwd(), ".env")
          if not os.path.exists(env_file):
              warnings.warn("can't read {0} - it doesn't exist".format(env_file))
          else:
              self.__import_vars(env_file)
docs: Imports .env file.