code: def add_content_ratings(self, app_id, submission_id, security_code):
          
          url = self.url('content_ratings') % app_id
          return self.conn.fetch('POST', url,
                                 {'submission_id': '%s' % submission_id,
                                  'security_code': '%s' % security_code
                                  })
docs: Add content ratings to the web app identified by by ``app_id``,
          using the specified submission id and security code.
  
          :returns: HttpResponse:
              * status_code (int) 201 is successful