在安装Python 2.7.9而不是最新的2.7.10的情况下，以前我可以brew versions python通过在brew中提交SHA来简单地使用和查看所有Python公式版本，然后将其检出以安装特定版本。这是brew versions python输出示例：

$ brew versions python
Warning: brew-versions is unsupported and will be removed soon.
You should use the homebrew-versions tap instead:
  https://github.com/Homebrew/homebrew-versions
2.7.9    git checkout 667284f /usr/local/Library/Formula/python.rb
2.7.8    git checkout f26ca5c /usr/local/Library/Formula/python.rb
2.7.7    git checkout d48206e /usr/local/Library/Formula/python.rb
2.7.6    git checkout 3c64184 /usr/local/Library/Formula/python.rb
2.7.5    git checkout a04b443 /usr/local/Library/Formula/python.rb
2.7.3    git checkout 865f763 /usr/local/Library/Formula/python.rb
2.7.4    git checkout 280581d /usr/local/Library/Formula/python.rb
2.7.2    git checkout 97c6869 /usr/local/Library/Formula/python.rb
2.7.1    git checkout 83ed494 /usr/local/Library/Formula/python.rb
2.7      git checkout 1bf3552 /usr/local/Library/Formula/python.rb
2.6.5    git checkout acd49f7 /usr/local/Library/Formula/python.rb
2.6.4    git checkout 843bff9 /usr/local/Library/Formula/python.rb
2.6.3    git checkout 5c6cc64 /usr/local/Library/Formula/python.rb

但是最新版本的brew已经取消了对它的versions支持，而且我不了解如何使用https://github.com/Homebrew/homebrew-
versions安装以前的Python
。如何实际安装Python 2.7.9而不是较新的2.7.10？

我想知道如何使用homebrew-versions而不是更简单的方法brew versions。

这样，brew versions我就可以轻松地从该特定公式中看到所有版本（请看一下上面通过吐出的Python版本brew versions python）。从doc来看，没有明确的方法可以达到相同的结果brew versions python。