title: pandas join DataFrame force suffix?
body: <p>How can I force a suffix on a merge or join.  I understand it's possible to provide one if there is a collision but in my case I'm merging df1 with df2 which doesn't cause any collision but then merging again on df2 which uses the suffixes but I would prefer for each merge to have a suffix because it gets confusing if I do different combinations as you could imagine.</p>