Import error on flask.helpers locked_cached_property

[rezib]

Build failure on Debian Trixie:

make[1]: Leaving directory '/build/fatbuildr-2.1.0.rc1'
   dh_auto_test -O--buildsystem=pybuild
I: pybuild base:311: cd /build/fatbuildr-2.1.0.rc1/.pybuild/cpython3_3.12/build; python3.12 -m unittest discover -v 
/build/fatbuildr-2.1.0.rc1/.pybuild/cpython3_3.12/build/fatbuildr/utils.py:91: SyntaxWarning: invalid escape sequence '\-'
  return re.sub("[^A-Za-z0-9\-]+", "", re.sub("/", "-", stem))
fatbuildr.protocols.http.server (unittest.loader._FailedTest.fatbuildr.protocols.http.server) ... ERROR

======================================================================
ERROR: fatbuildr.protocols.http.server (unittest.loader._FailedTest.fatbuildr.protocols.http.server)
----------------------------------------------------------------------
ImportError: Failed to import test module: fatbuildr.protocols.http.server
Traceback (most recent call last):
  File "/usr/lib/python3.12/unittest/loader.py", line 429, in _find_test_path
    package = self._get_module_from_name(name)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/unittest/loader.py", line 339, in _get_module_from_name
    __import__(name)
  File "/build/fatbuildr-2.1.0.rc1/.pybuild/cpython3_3.12/build/fatbuildr/protocols/http/server/__init__.py", line 24, in 
    from flask.helpers import locked_cached_property
ImportError: cannot import name 'locked_cached_property' from 'flask.helpers' (/usr/lib/python3/dist-packages/flask/helpers.py)


----------------------------------------------------------------------
Ran 1 test in 0.001s

FAILED (errors=1)
E: pybuild pybuild:389: test: plugin distutils failed with: exit code=1: cd /build/fatbuildr-2.1.0.rc1/.pybuild/cpython3_3.12/build; python3.12 -m unittest discover -v 

Full build log: https://build.rackslab.io/devs/watch/3776f29b-27e1-4ea7-b73d-f27815016aac.html