code: async def container(self, container=None, container_type=None, params=None, obj=None):
          
          if hasattr(container_type, 'kv_serialize'):
              container = container_type() if container is None else container
              return await container.kv_serialize(self, elem=container, elem_type=container_type, params=params, obj=obj)
  
          # Container entry version + container
          if self.writing:
              return await self.container_dump(container, container_type, params, obj=obj)
          else:
              return await self.container_load(container_type, params=params, container=container, obj=obj)
docs: Loads/dumps container
          :return: