Original patch by Erik Johansson, slightly updated by Meador Inge.

Original patch by Peter Saveliev.

Issue #21905: Avoid RuntimeError in pickle.whichmodule() when sys.modules is mutated while iterating.

Patch by Olivier Grisel.

Issue #21905: Avoid RuntimeError in pickle.whichmodule() when sys.modules is mutated while iterating.

Patch by Olivier Grisel.

argument to allow batching of tasks in child processes and improve
performance of ProcessPoolExecutor.  Patch by Dan O'Reilly.

more helpful error message for unsupported or mismatched types of arguments.

"xmlcharrefreplace", and "surrogatepass" error handlers.

"xmlcharrefreplace", and "surrogatepass" error handlers.

(including empty directories) in ZIP file.

(including empty directories) in ZIP file.

Patch by Éric Araujo with help from Lars Gustäbel.

Patch by Christian Heimes and Alex Gaynor.

A debian code search (by Tshepang Lekhonkhobe) turned up only one package
checking email.__version__...and it was the 2.7-only mailman package.  Since
Barry approves this change, it seems safe enough to make it...

Reported by Scott Hinton on docs@.

The test needs to be skipped if unicodedata is either part of the
main binary (a repackaging of cpython on Windows?) or has python
source (pypy?).  PEP 3147 makes __file__ point to the .py source,
so we need to change the extension check from looking for the
old .pyc/.pyo to just looking for .py.

Note that this skip should never trigger on CPython itself, so
one could argue it should be dropped instead.  But since it exists,
why risk breaking someone else's python.

characters (U+0000..U+001f and U+007f).

Closes #22540: speed up PyObject_IsInstance and PyObject_IsSubclass in the common case that the second argument has metaclass "type".

Python3 does not have the bug covered by the issue.