def delete(self, doc):
        if doc.id is None:
            raise DatabaseException('Document does not have id')
        if doc.sid is None:
            try:
                rs = self.db.docs.remove({'id': doc.id}, safe=True)
                assert rs['n'] == 1
            except Exception as e:
                raise DatabaseException(e)
            return None
        doc.data = None
        return self.update(doc)
def setUp(self):
        super(ExplorationVoiceoverApplicationUnitTest, self).setUp()
        self.signup('author@example.com', 'author')
        self.author_id = self.get_user_id_from_email('author@example.com')

        self.signup('reviewer@example.com', 'reviewer')
        self.reviewer_id = self.get_user_id_from_email('reviewer@example.com')

        self.voiceover_application = (
            suggestion_registry.ExplorationVoiceoverApplication(
                'application_id', 'exp_id', suggestion_models.STATUS_IN_REVIEW,
                self.author_id, None, 'en', 'audio_file.mp3', '<p>Content</p>',
                None))