eed3si9n/learning-scalaz — pull request #3 by xuwei-k (2013-05-13 17:14:55+00:00)
Title: fix 15/b.md

![screen shot 2013-05-14 at 2 14 07](https://f.cloud.github.com/assets/389787/496999/8fac3260-bbf0-11e2-8004-7e7c4c22635b.png)