Method populate

lib/sqlalchemy/orm/events.py:685–708

(
        cls,
        class_: Union[DeclarativeAttributeIntercept, DeclarativeMeta, type],
        subject: Union[ClassManager[_O], Mapper[_O]],
    )

    @classmethod
    def populate(
        cls,
        class_: Union[DeclarativeAttributeIntercept, DeclarativeMeta, type],
        subject: Union[ClassManager[_O], Mapper[_O]],
    ) -> None:
        for subclass in class_.__mro__:
            if subclass in cls.all_holds:
                collection = cls.all_holds[subclass]
                for (
                    event_key,
                    raw,
                    propagate,
                    retval,
                    kw,
                ) in collection.values():
                    if propagate or subclass is class_:
                        # since we can't be sure in what order different
                        # classes in a hierarchy are triggered with
                        # populate(), we rely upon _EventsHold for all event
                        # assignment, instead of using the generic propagate
                        # flag.
                        event_key.with_dispatch_target(subject).listen(
                            raw=raw, propagate=False, retval=retval, **kw
                        )


class _InstanceEventsHold(_EventsHold[_ET]):