'This is called only when the server starts "cold", i.e. after a
shutdown or a reset.'

def at_server_cold_start(self):

    from evennia.objects.models import ObjectDB
    ObjectDB.objects.clear_all_sessids()
    from evennia.scripts.models import ScriptDB
    for script in ScriptDB.objects.filter(db_persistent=False):
        script.stop()
    if GUEST_ENABLED:
        for guest in PlayerDB.objects.all().filter(db_typeclass_path=settings.BASE_GUEST_TYPECLASS):
            for character in guest.db._playable_characters:
                if character:
                    character.delete()
            guest.delete()
    if SERVER_STARTSTOP_MODULE:
        SERVER_STARTSTOP_MODULE.at_server_cold_start()
