Guido, do you have an option on this?  IIRC, this was an API you created.

Nick's thought (posted on twitter) is that 'filter(None, sep.split(input)' already covers the "drop the empty values" case. 

My feelings are mixed.  Though I've never needed in practice, it would be nice if the whitespace removal algorithm could be customized to just a space or just a tab.   On the other hand, I think the new parameter would make the API more confusing and harder to learn.  It might be better to just document either the filter(None) approach or a simple regex for the less common cases.