def _event_on_first_init(manager, cls):

    instrumenting_mapper = manager.info.get(_INSTRUMENTOR)
    if instrumenting_mapper:
        if Mapper._new_mappers:
            configure_mappers()
Initial mapper compilation trigger.
dataset/ETHPy150Open goFrendiAsgard/kokoropy/kokoropy/packages/sqlalchemy/orm/mapper.py/_event_on_first_init