seen in the second focal test rebuild
https://launchpadlibrarian.net/471775802/buildlog_ubuntu-focal-amd64.python-babel_2.6.0+dfsg.1-1ubuntu1_BUILDING.txt.gz
debian/rules override_dh_auto_build
make[1]: Entering directory '/<<BUILDDIR>>/python-babel-2.6.0+dfsg.1'
pyversions: missing X(S)-Python-Version in control file, fall back to debian/pyversions
pyversions: missing debian/pyversions file, fall back to supported versions
py3versions: no X-Python3-Version in control file, using supported versions
dh_auto_build -O--buildsystem=python_distutils
dh_auto_build: warning: Please use the third-party "pybuild" build system instead of python-distutils
dh_auto_build: warning: This feature will be removed in compat 12.
pyversions: missing X(S)-Python-Version in control file, fall back to debian/pyversions
pyversions: missing debian/pyversions file, fall back to supported versions
# Generate the localedata folder data out of the xml files
# downloaded in debian/repack
scripts/import_cldr.py common
/usr/bin/env: ‘python’: No such file or directory
make[1]: *** [debian/rules:16: override_dh_auto_build] Error 127
make[1]: Leaving directory '/<<BUILDDIR>>/python-babel-2.6.0+dfsg.1'
make: *** [debian/rules:10: build] Error 2
dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2
migration to the release pocket blocked by bug 1871610 in sphinx.