The solution to pycharm's unsuccessful download through pip

As in the title, the pip download using pycharm has been unsuccessful, regardless of whether the ladder is attached or not.

After several searches, it may be a matter of trust in the source of the downloaded mirror image, and it is enough to add trust in the source of the downloaded mirror image

for example:

pip install torchvision -i http://pypi.douban.com/simple --trusted-host pypi.douban.com

The download source can be replaced with another.

Tsinghua University: https://pypi.tuna.tsinghua.edu.cn/simple/
Aliyun: http://mirrors.aliyun.com/pypi/simple/

Douban Source: http://pypi.douban.com/simple/University
of Science and Technology of China: http://pypi.mirrors.ustc.edu.cn/simple/Huazhong
University of Science and Technology: http://pypi.hustunique.com/
Tencent source: http://mirrors.cloud.tencent.com/pypi/simple
Huawei mirror source: https://repo.huaweicloud.com/repository/pypi/simple/