Pylons/webob — pull request #4 by cwebber (2011-10-18 20:12:11+00:00)
Title: Fix NilAccept.best_match() so an empty "offers" + default_match picks def

Fix NilAccept.best_match() so an empty "offers" + default_match picks default

Prior to this, NilAccept.best_match([], default_match="default") threw:
UnboundLocalError: local variable 'best_offer' referenced before assignment

Also added a relevant test.