fix comment for is_none
@ -4015,7 +4015,7 @@ fn main() {
book_hashmap.insert(1, "L'Allemagne Moderne");
if book_hashmap.get(&1).is_none() { // is_none() returns a bool: true if it's Some, false if it's None
if book_hashmap.get(&1).is_none() { // is_none() returns a bool: true if it's None, false if it's Some
book_hashmap.insert(1, "Le Petit Prince");
}