def _load_data(self):
        self.print_step("Loading some data")
        self.room_mapping = _get_room_mapping()
        self.venue_mapping = {location.name: location for location in Location.query}
        self.all_users_by_email = {}
        for user in User.query.options(joinedload('_all_emails')):
            if user.is_deleted:
                continue
            for email in user.all_emails:
                self.all_users_by_email[email] = user