python - Django one line datetime if null -

i'd this:

class ventegroupee(models.model):     date_v_debut = models.datetimefield(         default=datetime.now,         editable=true     )     date_v_fin = models.datetimefield(         default=none,         null=true,         editable=true,         blank=true     )      def __str__(self):         return "{0} - ({1} -> {2})".format(             self.id,             dateformat(self.date_v_debut).format('js f y h:i')  if self.date_v_debut else 'infinity',             dateformat(self.date_v_fin).format('js f y h:i') if self.date_v_fin else 'infinity'         ) 

but 2 last lines ugly (date_v_debut , date_v_fin may null need check). there nice "pythonic"/"djangostic" way of doing this?

you create helper function format date.

def format_date(value)     return dateformat(value).format('js f y h:i') if value else 'infinity' 

then __str__ method simplifies to

def __str__(self):     return "{0} - ({1} -> {2})".format(         self.id,         format_date(self.date_v_debut),         format_date(self.date_v_fin),     )