Go中函数中返回变量的数量可变

I wonder if there is a way to implement a function that behaves similar to map getter: it returns return value as first argument and (optionally assigned) second value ok as second argument. So I need function f that I can call in following ways:

value1 := f(1)
value2, ok := f(2)

No, it can't be done, the only option is to return a pointer and check if it's nil.

if v := f(10); v != nil {
     //stuff
}