code: def refresh_token(self, refresh_token):
          '''return origin json'''
          url = 'https://api.youku.com/oauth2/token.json'
          data = {'client_id': self.client_id,
                  'grant_type': 'refresh_token',
                  'refresh_token': refresh_token}
          r = requests.post(url, data=data)
          check_error(r)
          return r.json(f refresh_token(self, refresh_token):
          '''return origin json'''
          url = 'https://api.youku.com/oauth2/token.json'
          data = {'client_id': self.client_id,
                  'grant_type': 'refresh_token',
                  'refresh_token': refresh_token}
          r = requests.post(url, data=data)
          check_error(r)
          return r.json()
docs: return origin json