non-iterator-returned:76:FirstBadIterator.__iter__:__iter__ returns non-iterator
non-iterator-returned:82:SecondBadIterator.__iter__:__iter__ returns non-iterator
non-iterator-returned:88:ThirdBadIterator.__iter__:__iter__ returns non-iterator
non-iterator-returned:94:FourthBadIterator.__iter__:__iter__ returns non-iterator