This caused an exception to be raised later than expected.

Use the cleaner looking @property style for __dict__.
Move _replace() to be just after make() to indicate that
it is a core method on named tuples.

to the new section.

  in urllib.request.urlopen() is fixed to match the code.

characters() and ignorableWhitespace() methods.  Original patch by Sebastian
Ortiz Vasquez.

distutils.cfg when a venv is active.

codecs.open().

broke backwards compatibility.