It's not O(1). You are only calling the API once, but if you put in a larger list the time will increase in accordance to whatever the complexity is of the sort

It's not O(1). You are only calling the API once, but if you put in a larger list the time will increase in accordance to whatever the complexity is of the sorting happening behind the scenes. Calling this O(1) would be like saying qsort is O(1) because you are only calling the function once.