ddebin/DDExpandableButton — pull request #2 by stevemoser (2012-12-17 14:18:06+00:00)
Title: Check self against nil

This could fail 6% of the time. Always check if your object is not nil against nil.

http://www.mikeash.com/pyblog/friday-qa-2012-12-14-objective-c-pitfalls.html