Function _mapper_fn

lib/sqlalchemy/orm/_orm_constructors.py:2154–2178

Placeholder for the now-removed ``mapper()`` function. Classical mappings should be performed using the :meth:`_orm.registry.map_imperatively` method. This symbol remains in SQLAlchemy 2.0 to suit the deprecated use case of using the ``mapper()`` function as a target for ORM event

(*arg: Any, **kw: Any)

def _mapper_fn(*arg: Any, **kw: Any) -> NoReturn:
    """Placeholder for the now-removed ``mapper()`` function.

    Classical mappings should be performed using the
    :meth:`_orm.registry.map_imperatively` method.

    This symbol remains in SQLAlchemy 2.0 to suit the deprecated use case
    of using the ``mapper()`` function as a target for ORM event listeners,
    which failed to be marked as deprecated in the 1.4 series.

    Global ORM mapper listeners should instead use the :class:`_orm.Mapper`
    class as the target.

    .. versionchanged:: 2.0  The ``mapper()`` function was removed; the
       symbol remains temporarily as a placeholder for the event listening
       use case.

    """
    raise InvalidRequestError(
        "The 'sqlalchemy.orm.mapper()' function is removed as of "
        "SQLAlchemy 2.0.  Use the "
        "'sqlalchemy.orm.registry.map_imperatively()` "
        "method of the ``sqlalchemy.orm.registry`` class to perform "
        "classical mapping."
    )


def dynamic_loader(