1👍
✅
format_date
would be great here, it get a string representation of a date according to the current locale
first we import it from django.utils import formats
then change your code like that
self.success_message = (
f"Eingeschrieben für <b>{formats.date_format(self.date, 'l')}</b>, "
f"den {formats.date_format(self.date, 'j. F Y')}.".replace(" 0", " ")
)
Source:stackexchange.com