instances.

http://mail.python.org/pipermail/python-dev/2008-January/076626.html and issue
1965.

in the same code unit. The fix is essentially the same as the fix for a
previous bug identifying 0. and -0.

this patch to py3k.

also noticed and fixed a bug in Rational's forward operators (they were
claiming all instances of numbers.Rational instead of just the concrete types).

answer if the input iterable had a duplicate element
(two calls to toggle() reverse each other).  Borrow
the correct code from sets.py.

The previous change was causing a segfault after multiple calls to Py_Initialize() and Py_Finalize().

Patch #1970 by Antoine Pitrou: Speedup unicode whitespace and linebreak detection. The speedup is about 25% for split() (571 / 457 usec) and 35% (175 / 127 usec )for splitlines()

the file.