max { return concat[:max], nil } else { return concat, nil } } } } } func concatenate(s1 string, s2 string) (string, error) { // ... }"> max { return concat[:max], nil } else { return concat, nil } } } } } func concatenate(s1 string, s2 string) (string, error) { // ... }"> max { return concat[:max], nil } else { return concat, nil } } } } } func concatenate(s1 string, s2 string) (string, error) { // ... }"> 
func join(s1, s2 string, max int) (string, error) {
if s1 == "" {
return "", errors.New("s1 is empty")
} else {
if s2 == "" {
return "", errors.New("s2 is empty")
} else {
concat, err := concatenate(s1, s2)
if err != nil {
return "", err
} else {
if len(concat) > max {
return concat[:max], nil
} else {
return concat, nil
}
}
}
}
}
func concatenate(s1 string, s2 string) (string, error) {
// ...
}

If you tried to to understand the join function above, it requires a cognitive effort, despite of its correctness it’s harder to understand it quickly.

after i