Serialize ratings object as JSON-formatted string

def get_json(self):
        """Serialize ratings object as JSON-formatted string"""
        ratings_dict = {
            'category': self.category,
            'date': self.date,
            'day': self.weekday,
            'next week': self.next_week,
            'last week': self.last_week,
            'entries': self.entries,
            'url': self.url
        }
        return to_json(ratings_dict)