Log Message:
python39: added version 3.9.0

3.9.0 Release highlights

New syntax features:

PEP 584, union operators added to dict;
PEP 585, type hinting generics in standard collections;
PEP 614, relaxed grammar restrictions on decorators.

New built-in features:

PEP 616, string methods to remove prefixes and suffixes.

New features in the standard library:

PEP 593, flexible function and variable annotations;
os.pidfd_open() added that allows process management without races and signals.

Interpreter improvements:

PEP 573, fast access to module state from methods of C extension types;
PEP 617, CPython now uses a new parser based on PEG;
a number of Python builtins (range, tuple, set, frozenset, list, dict) are now \ 
sped up using PEP 590 vectorcall;
garbage collection does not block on resurrected objects;
a number of Python modules (_abc, audioop, _bz2, _codecs, _contextvars, _crypt, \ 
_functools, _json, _locale, math, operator, resource, time, _weakref) now use \ 
multiphase initialization as defined by PEP 489;
a number of standard library modules (audioop, ast, grp, _hashlib, pwd, \ 
_posixsubprocess, random, select, struct, termios, zlib) are now using the \ 
stable ABI defined by PEP 384.

New library modules:

PEP 615, the IANA Time Zone Database is now present in the standard library in \ 
the zoneinfo module;
an implementation of a topological sort of a graph is now provided in the new \ 
graphlib module.

Release process changes:

PEP 602, CPython adopts an annual release cycle.