tree ef7c3f5fe7bcc9d8b8c1b73c08997dfe7cc5741e
parent dfe109e33f95f0c2cad5465347a62ac3ec14ca06
author Andrew Svetlov <andrew.svetlov@gmail.com> 1355745676 +0200
committer Andrew Svetlov <andrew.svetlov@gmail.com> 1355745676 +0200

Update example: Counter.subtract returns None, not self