code: func (obj *object) Until(f func(*Term, *Term) bool) bool {
  	err := obj.Iter(func(k, v *Term) error {
  		if f(k, v) {
  			return errStop
  		}
  		return nil
  	})
  	return err != nil
  }
docs: // Until calls f for each key-value pair in the object. If f returns true,
  // iteration stops.