orm.go
func (f *Field) RowsPreviousLimit(rowIDOrKey interface{}, limit int64) *PQLRowsQuery {
	idKey, err := formatIDKey(rowIDOrKey)
	if err != nil {
		return NewPQLRowsQuery("", f.index, err)
	}
	if limit < 0 {
		return NewPQLRowsQuery("", f.index, errors.New("rows limit must be non-negative"))
	}
	text := fmt.Sprintf("Rows(field='%s',previous=%s,limit=%d)", f.name, idKey, limit)
	return NewPQLRowsQuery(text, f.index, nil)
}
func (f *Field) RowsPreviousLimit(rowIDOrKey interface{}, limit int64) *PQLRowsQuery {
	idKey, err := formatIDKey(rowIDOrKey)
	if err != nil {
		return NewPQLRowsQuery("", f.index, err)
	}
	if limit < 0 {
		return NewPQLRowsQuery("", f.index, errors.New("rows limit must be non-negative"))
	}
	text := fmt.Sprintf("Rows(field='%s',previous=%s,limit=%d)", f.name, idKey, limit)
	return NewPQLRowsQuery(text, f.index, nil)
}
// RowsPreviousLimit creates a Rows query with the given previous row ID/key and limit