In Python, a function named "sort" could take an array and return an integer. Or None. Or crash. So knowing that it returns an array of integers is an improveme

In Python, a function named "sort" could take an array and return an integer. Or None. Or crash. So knowing that it returns an array of integers is an improvement over the untyped case. Types like "returns an array" or Java's checked exceptions are attempts at narrowing the possible behaviors from a function.