non-iterator-returned:73:4:FirstBadIterator.__iter__:__iter__ returns non-iterator
non-iterator-returned:79:4:SecondBadIterator.__iter__:__iter__ returns non-iterator
non-iterator-returned:85:4:ThirdBadIterator.__iter__:__iter__ returns non-iterator
non-iterator-returned:91:4:FourthBadIterator.__iter__:__iter__ returns non-iterator
