Workable gettext

with_global.py

# workalendar/i18n.py

import gettext
import collections


_ = lambda x: x


def get_translation_for_language(language: str) -> gettext.Translations:
    return gettext.translation("mydomain", "/path/to/translations", [language])


def gettext(message:str) -> str:
    return translations[get_current_language()].gettext(message)


def ngettext(count: int, message: str) -> str:
    return translations[get_current_language()].ngettext(count, message)


def pgettext(context: str, message: str) -> str:
    # 3.8+ only :o
    return translations[get_current_language()].pgettext(context, message)

...

def get_current_language() -> str:
    # Do some magic: read a module variable or a threadlocal or a ContextVar or whatever. Your business.
    

def set_current_translation(language: str) -> None:
    # Do some magic: write a module variable or a threadlocal or a ContextVar or whatever. Your business.
    # a.k.a translation.activate    

@contextlib.contextmanager
def override_language(language: str):
    prev = get_current_language()
    set_current_language(language)
    try:
        yield
    finally:
        set_current_language(prev)

translations = collections.defaultdict(get_translation_for_language)

# workalendar/elsewhere.py

from workalendar.i18n import _, translate

holiday_name = _("Pâques")

def easter_name():
    set_current_language("fr")
    return gettext(holiday_name)
    #also works with
    with translation_override("de"):
        gettext("Pâques")
    # now back to french

without_global.py

# workalendar/i18n.py

import gettext
import collections


_ = lambda x: x


def get_translation_for_language(language: str) -> gettext.Translations:
    return gettext.translation("mydomain", "/path/to/translations", [language])


def translate(language: str, message:str) -> str:
    return translations[language].gettext(message)


def translate_count(language: str, count: int, message: str) -> str:
    return translations[language].ngettext(count, message)


def translate_context(language: str, context: str, message: str) -> str:
    # 3.8+ only :o
    return translations[language].pgettext(context, message)


translations = collections.defaultdict(get_translation_for_language)
  
# workalendar/elsewhere.py

from workalendar.i18n import _, translate

holiday_name = _("Pâques")

def easter_name(language):
    return translate(language, holiday_name)
    # or
    return translate(language, _("Pâques"))

Hm, I think gettext.translation("mydomain", "/path/to/translations", [language]) is really not meant to be called multiple times...