yulintan

## service.go
package service

import "errors"

func FlatternArray(a interface{}, existing []int) ([]int, error) {
	switch val := a.(type) {
	case int:
		return append(existing, val), nil
	case []int:
		return append(existing, val...), nil

## export_test.go
package service

var CalculateSum = calculateSum
	package service

	import "errors"

	func FlatternArray(a interface{}, existing []int) ([]int, error) {
	switch val := a.(type) {
	case int:
	return append(existing, val), nil
	case []int:
	return append(existing, val...), nil