Based on patch by Tycho Andersen.

WeakValueDictionary when collecting from another thread.

Patch by Dhushyanth Ramasamy.

Based on patch by Patrila.

Based on suggestion from Fumihiro Bessho.

including encoding not recognized by codecs.lookup.

Fixed running MiscTests in test_xml_etree_c.

Original patch by Rasmus Villemoes.

Issue #28383: __hash__ documentation recommends naive XOR to combine but this
is suboptimal. Update the doc to suggest to reuse the hash() method using a
tuple, with an example.

when a GC collection happens in another thread.

Original patch and report by Armin Rigo.

Improved the documentation and tests for make_archive().
Improved error handling when corresponding compress module is not available.
External zip executable is now used if the zlib module is not available.

of old-style classes.