【报错】安装scrapy时Could not build wheels for cryptography which use PEP 517 and cannot be installed direc

问题：
Windows在安装scrapy时候报错

error: Microsoft Visual C++ 14.0 or greater is required. Get it with “Microsoft C++ Build Tools”: https://visualstudio.microsoft.com/visual-cpp-build-tools/

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Failed building wheel for cryptography
Running setup.py clean for cryptography
Failed to build cryptography
Could not build wheels for cryptography which use PEP 517 and cannot be installed directly

解决：
1、安装 Microsoft visual c++ 14.0

https://964279924.ctfile.com/fs/1445568-239446865

2、若出现.Net framework版本过低，小于4.5的最低版本要求：
【若没有，跳过这一步】

重新安装 .Net framework 更高的版本：
https://support.microsoft.com/en-us/help/3151800/the-net-framework-4-6-2-offline-installer-for-windows

再回第1步
3、重启电脑，重新安装scrapy

pip3 install scrapy -i https://pypi.tuna.tsinghua.edu.cn/simple/