Pagination in get_discussions_by_feed not working

[hrosspet]

According to condenser api documentation the discussion_query parameter should have the following structure:

{
 "tag": "",
 "start_author": "",
 "start_permlink": "",
 "limit": 100
}

The tag key and limit key work nicely, but the function seems to give the same response regardless of how the start_author and start_permlink are set. https://github.com/steemit/steem-python/blob/58071e4cfcbbf2aa8e0b2b37e3238dbab6d9cdf0/steem/steemd.py#L344

I also tried an alternative function steem.steemd.get_feed but its comment field has different keys than get_discussions_by_feed, so it's not suitable.