code: def upgrade_config(self, contents):
          
          schema = UpgradeConfigSchema()
          resp = self.service.post(self.base,
                                   params={'process': 'upgrade'}, json={'contents': contents})
          return self.service.decode(schema, resp)
docs: Process config contents with cdrouter-cli -upgrade-config.
  
          :param contents: Config contents as string.
          :return: :class:`configs.UpgradeConfig <configs.UpgradeConfig>` object
          :rtype: configs.UpgradeConfig