Runtime of sorted() on an already sorted list?

Question

Just curious, will the built-in sorted() function just note a list is already sorted and return the same list in constant time?

x = [1, 2, 3, 4, 5]
y = sorted(x)

Answer 1

No. It will create a new list and add the values from the existing list in sorted order which in your case is already sorted. It will walk through the entire existing list in O(n) times for a list of length n. So it will not return a list in constant time.

And there is no way the sorted() function can know that list is sorted until the entire list is iterated over by it which obviously cannot be done in constant time.