gpsoauth allows python code to use the "master token" flow that KB Sriram described at http://sbktech.blogspot.com/2014/01/inside-android-play-services-magic.html.
This can be useful when writing code that poses as a Google app, like gmusicapi does.
Many thanks to Dima Kovalenko for reverse engineering the EncryptedPasswd signature in http://codedigging.com/blog/2014-06-09-about-encryptedpasswd.