How to retrieve membership level

Hi,

I have a (custom) post category page that I want to restrict to a certain membership level. So far, I can restrict it to logged in users by simply do an
if (is_user_logged_in() && have_posts()) {...} check.
However, then of course users of all memership levels can see the content.
Is there a way to check if the user’s membership level is ‘partner’?
I already tried to find some clues in the plugin code but didn’t really succeeded ??

Thank you in anticipation!