Facebook sdk for python cannot limit page feed query with 'since'

I'm trying to fetch all posts on specific page after certain time. I'm using this facebook-sdk for python. Last post on the page has been posted 30th may 2017. The problem with my query is that even if I try to limit the query with since='2017-06-06T09:00:00+00:00', it always returns my posts from the page.

My timestamp is in exact same format as I get it if I query it from the facebook.

Here's the code

facebook_api = facebook.GraphAPI(access_token='FACEBOOK_PAGE_ACCESS_TOKEN')facebook_feed = facebook_api.get_object(            id=FACEBOOK_PAGE_ID,            fields='feed',            since='2017-06-06T09:00:00+0000')

I don't have a clue what kind of api query url facebook-sdk for python creates with this code and I don't know how to check that.

I also tried converting timestamp to unix timestamp with online tool, but it didn't work either.