Issue #17351: Modernize the pure Python property() example.
merge
Inherit from object() for consistency
merge
Fix typo in PyDict_SetDefault docs.
Update code to increment and decrement using the cleaner += 1 and -= 1 style.
Issue #17385: Fix quadratic behavior in threading.Condition
Improve variable names
#11963: remove human verification from test_parser and test_subprocess.
#11963: merge with 3.2.
#11963: merge with 3.3.
Issue #15806: Add contextlib.ignored().
Remove debug print.
#17351: remove "object" inheritance from docs.  Patch by Phil Elson.
#17351: merge with 3.2.
#17351: merge with 3.3.