[pygame] Collision detection help - colliderect

[IamScuzzo <i.am.scuzzo@xxxxxxxxx>]

I am trying to check a collision between "b" and "B". "b" is the
bullet sprite from the Bullet class, and B is the barney sprite from
the Barney class.

Link: http://pastebin.com/m4d7304fc

Right now nothing happens when I run the game, no collision detections
and no error messages. I cant figure out what I am doing wrong. It was
complaining about how b isnt defined so I made it global, same with B.