def _load_option(self, conf, opt):
        try:
            return self._processed[conf][opt]
        except KeyError:
            if (conf, opt) in self._ref_stack:
                raise exceptions.YamlLoopException(conf, opt, self._ref_stack)
            self._ref_stack.append((conf, opt))

            self._cache(conf)
            try:
                raw_value = self._cached[conf][opt]
            except __HOLE__:
                try:
                    cur_conf, cur_opt = self._ref_stack[-1]
                except IndexError:
                    cur_conf, cur_opt = None, None
                raise exceptions.YamlOptionNotFoundException(
                    cur_conf, cur_opt, conf, opt
                )
            result = self._process(raw_value)
            self._processed.setdefault(conf, {})[opt] = result

            self._ref_stack.pop()
            return result
dataset/ETHPy150Open openstack/anvil/anvil/cfg.py/YamlRefLoader._load_option