R. David Murray <rdmurray@bitdance.com> added the comment:
This is as documented:
http://docs.python.org/dev/3.0/library/io.html#io.TextIOBase.newlines
The keyword argument is named 'newline', the attribute is named 'newlines'. The attribute does not record what was passed to the newline argument, rather it records what newlines have been actually encountered.