Tweepy twitter oauth authentication not returning oauth_verifier

I am using a python library called "tweepy" for twitter. When I try to authorize the user, twitter is supposed to redirect to a callback url with auth_token an开发者_开发知识库d oauth_verifier. I am getting only auth_token in the url. Anyone else had the same problem?

Twitter only uses oauth_verifier (PINs) for desktop applications. For web applications, Twitter bypasses this and does not use it. You can re-check your application settings at http://dev.twitter.com/apps