code: def Managed(cls, manager, field, items):
          
          attrs = {
              "_manager": manager,
              "_manager_field": field,
          }
          if hasattr(cls, "create"):
              attrs['create'] = ManagedCreate(cls)
          cls = type(
              "%s.Managed#%s" % (
                  cls.__name__, manager.__class__.__name__), (cls,), attrs)
          return cls(items)
docs: Create a custom `ObjectSet` that is managed by a related `Object.`
  
          :param manager: The manager of the `ObjectSet`. This is the `Object`
              that manages this set of objects.
          :param field: The field on the `manager` that created this managed
              `ObjectSet`.
          :param items: The items in the `ObjectSet`.