Here is a patch which changes name of optional parameter of read(), read1(), peek(), and readline() methods to most common name "size" in the documentation and _pyio module. truncate() in _pyio fixed to conform with documentation. This changes are safe.

There is open question about readlines(). It's optional parameter named as:

"hint" in _pyio and the documentation;
"size" in bz2;
"sizehint" in codecs and mailbox.