String#insert method is destructive... inconsistent?

Hi all, I am relatively new to Ruby, and I am loving it! I have a long Python background, and one of the things I love about Ruby is that it is easier to know and even remember which methods are destructive and which just return a result. Looking through the “String” class methods, one sticks out: “insert”. Almost all others (and all that might be ambiguous), like “delete”, “sub”, etc., have both