Translation with string format at import time - django

Question

I have model with attribute like this:
new = models.BooleanField(default=False, verbose_name=_("Is new"),
help_text=_("By default product is marked as new by {0} days since creation.")
.format(settings.PRODUCT_IS_NEW_EXPIRATION_DAYS))
This unfortunately works for runserver command but when I want to run test it failes and I receive following error:
django.core.exceptions.AppRegistryNotReady: The translation infrastructure cannot be initialized before the apps registry is ready. Check that you don't make non-lazy gettext calls at import time.
This error is clear. I'm trying to use translations before apps are ready.
It is possible to have a translation that requires string formatting at import time?
Edit:
Traceback:
File "./manage.py", line 9, in <module>
execute_from_command_line(sys.argv)
File "django/core/management/__init__.py", line 354, in execute_from_command_line
utility.execute()
File "django/core/management/__init__.py", line 328, in execute
django.setup()
File "django/__init__.py", line 18, in setup
apps.populate(settings.INSTALLED_APPS)
File "django/apps/registry.py", line 85, in populate
app_config = AppConfig.create(entry)
File "django/apps/config.py", line 86, in create
module = import_module(entry)
File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
__import__(name)
File "haystack/__init__.py", line 57, in <module>
signal_processor_class = loading.import_class(signal_processor_path)
File "haystack/utils/loading.py", line 32, in import_class
module_itself = importlib.import_module(module_path)
File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
__import__(name)
File "utils/signals.py", line 12, in <module>
from products.models import Products
File "products/models/__init__.py", line 2, in <module>
from .carousel import ProductCarousel, ProductCarouselImage
File "products/models/carousel.py", line 10, in <module>
from products.models.product import Products
File "products/models/product.py", line 210, in <module>
class Products(models.Model):
File "products/models/product.py", line 241, in Products
help_text=(ugettext("By default product is marked as new by {0} days since creation.")).format(
File "django/utils/translation/__init__.py", line 84, in ugettext
return _trans.ugettext(message)
File "django/utils/translation/trans_real.py", line 330, in ugettext
return do_translate(message, 'ugettext')
File "django/utils/translation/trans_real.py", line 307, in do_translate
_default = _default or translation(settings.LANGUAGE_CODE)
File "django/utils/translation/trans_real.py", line 209, in translation
_translations[language] = DjangoTranslation(language)
File "django/utils/translation/trans_real.py", line 118, in __init__
self._add_installed_apps_translations()
File "django/utils/translation/trans_real.py", line 159, in _add_installed_apps_translations
"The translation infrastructure cannot be initialized before the "
django.core.exceptions.AppRegistryNotReady: The translation infrastructure cannot be initialized before the apps registry is ready. Check that you don't make non-lazy gettext calls at import time.

Answer 1

I tried to comment on the post but I can't since I don't have enough reputation. Have you tried formatting the help_text first and then translating it? Something like this:
help_text = _(
"By default product is marked as new by {} days since creation.".format(
settings.PRODUCT_IS_NEW_EXPIRATION_DAYS
)
)
new = models.BooleanField(default=False, verbose_name=_("Is new"),
help_text=help_text)
NOTE: .format is inside the ugettext