// OrderSlice is define for order's sort
type OrderSlice []*Order
func (o OrderSlice) Len() int { return len(o) }
func (o OrderSlice) Swap(i, j int) { o[i], o[j] = o[j], o[i] }
func (o OrderSlice) Less(i, j int) bool {
// OrderSlice is define for order's sort
type OrderSlice []*Order
func (o OrderSlice) Len() int { return len(o) }
func (o OrderSlice) Swap(i, j int) { o[i], o[j] = o[j], o[i] }
func (o OrderSlice) Less(i, j int) bool {