func ExampleSum() {
in := []int{1, 2, 3, 4}
out := generic.Sum(in).(int)
fmt.Println(out)
// Output: 10
}
func ExampleSum_slice() {
in := [][]int{[]int{1, 2}, []int{3, 4}}
out := generic.Sum(in).([]int)
fmt.Println(out)
// Output: [1 2 3 4]
}