python 3.10 incompat, exec FAILs @ "SystemError: PY_SSIZE_T_CLEAN macro must be defined for '#' formats"

[pgnd]

upgrading fedora 34 -> 35

now,

 python --version
  Python 3.10.0

dkimpy-milter is installed

 pip show dkimpy dkimpy-milter pymilter pynacl | egrep "Name:|Version:"
  Name: dkimpy
  Version: 1.0.5
  Name: dkimpy-milter
  Version: 1.2.2
  Name: pymilter
  Version: 1.0.4
  Name: PyNaCl
  Version: 1.4.0

outbound dkimpy-milter signing now fails

 2021-11-02T15:56:39.946644-04:00 mx dkimpy-milter[30551]: SystemError: PY_SSIZE_T_CLEAN macro must be defined for '#' formats
 2021-11-02T15:56:39.946668-04:00 mx dkimpy-milter[30551]: SystemError: PY_SSIZE_T_CLEAN macro must be defined for '#' formats
 2021-11-02T15:56:39.946688-04:00 mx dkimpy-milter[30551]: dkimpy-filter: milter claimed not to reply in state 9 but did anyway 4

noting

 Python 3.10: SystemError: PY_SSIZE_T_CLEAN macro must be defined for '#' formats
  https://gitlab.gnome.org/GNOME/libxml2/-/issues/203

 Parsing arguments and building values
  https://docs.python.org/3/c-api/arg.html
  "For all # variants of formats (s#, y#, etc.), the macro PY_SSIZE_T_CLEAN must be defined before including Python.h. On Python 3.9 and older, the type of the length argument is Py_ssize_t if the PY_SSIZE_T_CLEAN macro is defined, or int otherwise."

[Scott Kitterman (kitterman)]

Looks like a pymilter issue.

[Scott Kitterman (kitterman)]

Forwarded to pymilter where the problem is located. https://github.com/sdgathman/pymilter/issues/44