Test into

Changed one function around. Wasnt working before, fixed it, added chunksize argument. Not sure if we want this to be a pattern, where we add chunksize arguments for functions which use chunks.

Also the code looks ugly and can probably be done better. 
Yeah i wasn't quite sure what to do in this situation, since pytest gave me this error (should have read it, it's obvious now, thanks for pointing it out):

`ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()`

I think you have to put `.all()` or `.any()` on both sides by the way.