fdroid update fails in scan_apk_anrdoguard

The following command fails with androguard 4.0.2 (it succeeds with androguard 3.4.0a1). I've installed fdroidserver 2.2.1

fdroid update --use-date-from-apk --rename-apks --create-metadata --pretty

The output is

CRITICAL: Unknown exception found!
Traceback (most recent call last):
  File "/var/fdroid/bin/fdroid", line 22, in <module>
    fdroidserver.__main__.main()
  File "/var/fdroid/bin/fdroidserver/__main__.py", line 230, in main
    raise e
  File "/var/fdroid/bin/fdroidserver/__main__.py", line 211, in main
    mod.main()
  File "/var/fdroid/bin/fdroidserver/update.py", line 2246, in main
    apks, cachechanged = process_apks(apkcache, repodirs[0], knownapks,
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/var/fdroid/bin/fdroidserver/update.py", line 1626, in process_apks
    (skip, apk, cachethis) = process_apk(apkcache, apkfilename, repodir, knownapks,
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/var/fdroid/bin/fdroidserver/update.py", line 1486, in process_apk
    apk = scan_apk(apkfile)
          ^^^^^^^^^^^^^^^^^
  File "/var/fdroid/bin/fdroidserver/update.py", line 1235, in scan_apk
    scan_apk_androguard(apk, apk_file)
  File "/var/fdroid/bin/fdroidserver/update.py", line 1319, in scan_apk_androguard
    from androguard.core.bytecodes.apk import APK
ModuleNotFoundError: No module named 'androguard.core.bytecodes'