def check_prerequisites(self, awardee, dep_badge, award):
        if self.is_awarded_to(awardee):
            # Not unique, but badge auto-award from prerequisites should only
            # happen once.
            return None
        for badge in self.prerequisites.all():
            if not badge.is_awarded_to(awardee):
                # Bail on the first unmet prerequisites
                return None
        return self.award_to(awardee)
alternate: manage.py can't execute user commands
dataset/ETHPy150Open mozilla/django-badger/badger/models.py/Badge.check_prerequisites--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.2/tests/regressiontests/admin_scripts/tests.py/ManageAlternateSettings.test_custom_command