def _create_assignment(self, period, short_name, long_name, first_deadline,
publishing_time, delivery_types, anonymous):
assignment = Assignment(parentnode=period, short_name=short_name,
long_name=long_name,
first_deadline=first_deadline,
publishing_time=publishing_time,
delivery_types=delivery_types,
anonymous=anonymous)
assignment.full_clean()
assignment.save()
return assignment
