获取远端代理ip

def ips(self) -> Optional[List[str]]:
        """
        获取远端代理ip
        """
        if self.proxy and "X-Forwarded-For" in self._headers:
            val = cast(str, self.get('X-Forwarded-For'))
            ips = [i.strip() for i in val.split(",")]
            return ips if len(ips) > 0 else None
        return None