This was found by PVS-Studio:

V595 The 'def' pointer was utilized before it was verified
against nullptr. Check lines: 286, 292. pystate.c 286

Initial patch by Christian Heimes.

Use flush=True to try to get a warning which is missing in buildbots.

Use also f-string to make the code shorter.

* main.py: remove unused import
* runtest: simplify runtest_inner() parameters, reuse ns parameter

Issue #27128. When a Python function is called with no arguments, but all
parameters have a default value: use default values as arguments for the fast
path.

Issue #27539: Fix unnormalised Fraction.__pow__ result for negative exponent and base. Thanks Vedran Čačić.

According to PEP 249, cursor.description must be
available for any SELECT statements, such as those
that use CTEs.

Backported from https://github.com/ghaering/pysqlite/commit/f67fa9c898a4713850e16934046f0fe2cba8c44c

Additional test cases added by me.

have caused off-by-one-ulp results on certain platforms.

Multi-phase extension module import now correctly allows the
``m_methods`` field to be used to add module level functions
to instances of non-module types returned from ``Py_create_mod``.

Patch by Xiang Zhang.

Also try to clarify the find_spec() error message.

Patch by Xiang Zhang.