def METHOD_NAME(self, idx: int, spec: Dict) -> str:
    """解析来源自 External 的指标信息"""
    current = '<unknown>'
    if getitems(spec, 'external.target.averageValue') is not None:
        if len(self.statuses) > idx:
            ext_cur_avg_val = getitems(self.statuses[idx], 'external.current.averageValue')
            current = ext_cur_avg_val if ext_cur_avg_val else current
        return f"{current}/{getitems(spec, 'external.target.averageValue')} (avg)"
    else:
        if len(self.statuses) > idx:
            ext_cur_val = getitems(self.statuses[idx], 'external.current.value')
            current = ext_cur_val if ext_cur_val else current
        return f"{current}/{getitems(spec, 'external.target.value')}"