crash in python 3.10

[anarcat]

running this under Python 3.10+ on Debian bookworm crashes:

anarcat@angela:paperbackup$ python3 -c 'import qrencode ; version, size, data = qrencode.encode(b"test")'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python3/dist-packages/qrencode/__init__.py", line 47, in encode
    version, size, data = _encode(data, version, level, hint, True)
                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
SystemError: PY_SSIZE_T_CLEAN macro must be defined for '#' formats
anarcat@angela:paperbackup[1]$ 

also reported as https://bugs.debian.org/1032287 in debian.