def add_eager_constraints(self, models):
        key = '%s.%s' % (self._related.get_table(), self._other_key)

        self._query.where_in(key, self._get_eager_model_keys(models))
Set the constraints for an eager load of the relation.
dataset/ETHPy150Open sdispater/orator/orator/orm/relations/belongs_to.py/BelongsTo.add_eager_constraints