When downloading using pip is very slow, and even an error

pip._vendor.urllib3.exceptions.ReadTimeoutError: HTTPSConnectionPool(host=‘files.pythonhosted.org’, port=443): Read timed out.

Record the data source here:
1. Douban source: https://pypi.douban.com/simple
2. Tsinghua source: https://pypi.tuna.tsinghua.edu.cn/simple

when using it:

pip install pyinstaller -i https://pypi.douban.com/simple
pip install pyinstaller -i https://pypi.tuna.tsinghua.edu.cn/simple