Method before_configured

lib/sqlalchemy/orm/events.py:1084–1125

Called before a series of mappers have been configured. The :meth:`.MapperEvents.before_configured` event is invoked each time the :func:`_orm.configure_mappers` function is invoked, before the function has done any of its work. :func:`_orm.configure_mappers` is typi

(self)

    @event._omit_standard_example
    def before_configured(self) -> None:
        """Called before a series of mappers have been configured.

        The :meth:`.MapperEvents.before_configured` event is invoked
        each time the :func:`_orm.configure_mappers` function is
        invoked, before the function has done any of its work.
        :func:`_orm.configure_mappers` is typically invoked
        automatically as mappings are first used, as well as each time
        new mappers have been made available and new mapper use is
        detected.

        Similar events to this one include
        :meth:`.MapperEvents.after_configured`, which is invoked after a series
        of mappers has been configured, as well as
        :meth:`.MapperEvents.before_mapper_configured` and
        :meth:`.MapperEvents.mapper_configured`, which are both invoked on a
        per-mapper basis.

        This event can **only** be applied to the :class:`_orm.Mapper` class,
        and not to individual mappings or mapped classes::

            from sqlalchemy.orm import Mapper


            @event.listens_for(Mapper, "before_configured")
            def go(): ...

        Typically, this event is called once per application, but in practice
        may be called more than once, any time new mappers are to be affected
        by a :func:`_orm.configure_mappers` call.   If new mappings are
        constructed after existing ones have already been used, this event will
        likely be called again.

        .. seealso::

            :meth:`.MapperEvents.before_mapper_configured`

            :meth:`.MapperEvents.mapper_configured`

            :meth:`.MapperEvents.after_configured`

        """

    @event._omit_standard_example
    def after_configured(self) -> None: