"{0!r} does not exist in evaluation environment.".format(name) 问题解决方案

"{0!r} does not exist in evaluation environment.".format(name)
UndefinedEnvironmentName: 'extra' does not exist in evaluation environment.

 

 

原因：

setuptools版本太低（我的是20.7.0  ，实际上应该要升级到35.0.1）

解决：

pip install --upgrade setuptools