How to provide Return URL Verification with OpenID?

I am using the PHP OpenID library from http://openidenabled.com on my site. However, I just realised I need to support Return URL Verification. How can I do that with this class? I paged through the docs bu开发者_如何学Pythont I couldn't find anything.

Edit: forgot to mention it is a CONSUMER application.

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Here's a blog post that explains it all.