今天再安装 pyserial 的时候一直提示这个错误，
电脑代理什么的都关掉了还是有这个错误，然后根据 网上 的说明，添加添加信任主机选项后就成功安装上 pyserial 了。
pip --trusted-host pypi.tuna.tsinghua.edu.cn install pyserial
- CERTIFICATE_VERIFY_FAILED CERTIFICATE FAILED VERIFY PIPcertificate_verify_failed certificate certificate_verify_failed sslcertverificationerror certificate_verify_failed certificate failed 杂症certificate_verify_failed疑难certificate vertificate_verify_failed failed verify vertificate_verify_failed sslcertverificationerror certificate cannot verify github no-verify commit failed verify certificate unable verify axios verify