code: def plan(self, dir_or_plan=None, detailed_exitcode=IsFlagged, **kwargs):
          
          options = kwargs
          options['detailed_exitcode'] = detailed_exitcode
          options = self._generate_default_options(options)
          args = self._generate_default_args(dir_or_plan)
          return self.cmd('plan', *args, **options)
docs: refer to https://www.terraform.io/docs/commands/plan.html
          :param detailed_exitcode: Return a detailed exit code when the command exits.
          :param dir_or_plan: relative path to plan/folder
          :param kwargs: options
          :return: ret_code, stdout, stderr