## isupper ### Instructions Write a function that returns `true` if the `string` passed in parameter only contains uppercase characters, and that returns `false` otherwise. ### Expected function ```go func IsUpper(s string) bool { } ``` ### Usage Here is a possible program to test your function : ```go package main import ( "fmt" piscine ".." ) func main() { fmt.Println(piscine.IsUpper("HELLO")) fmt.Println(piscine.IsUpper("HELLO!")) } ``` And its output : ```console student@ubuntu:~/[[ROOT]]/test$ go build student@ubuntu:~/[[ROOT]]/test$ ./test true false student@ubuntu:~/[[ROOT]]/test$ ```