code: func NewRangeOp(object DomainObject) *RangeOp {
  	rop := &RangeOp{
  		conditioner: conditioner{
  			object:     object,
  			conditions: map[string][]*Condition{},
  		},
  	}
  	return rop
  }
docs: // NewRangeOp returns a new RangeOp instance