安装mock报错：ERROR: Could not find a version that satisfies the requirement mock (from versions: none)

把pip升级到最新版本：

C:\Users\n>python -m pip install --upgrade pip
Requirement already up-to-date: pip in c:\python37\lib\site-packages (20.0.2)

然后再安装mock即可：

C:\Users\n>pip install mock
Requirement already satisfied: mock in c:\python37\lib\site-packages (4.0.2)

使用上面的命令安装即可，我这里是已经安装成功了