strings2pot is useful to convert Apple .strings, Android/Java .xml or Google app resource bundle .arb files to POT gettext files.
pip install strings2pot
root@host$ strings2pot <STRINGS_FILE> <POT_FILE>
e.g.
root@host$ strings2pot Localizable.strings my_ios_app.pot root@host$ strings2pot values.xml my_android_app.pot
from strings2pot import strings2pot executed, error_message = strings2pot.run("Localizable.strings", "my_ios_app.pot")