A list is sorted in ascending order if it is empty or each item except the last one is less than or equal to its successor. Define a predicate isSorted that expects a list as an argument and returns True if the list is sorted or returns False otherwise. $($Hint: For a list of length $2$ or greater, loop through the list and compare pairs of items, from left to right, and return False if the first item in a pair is greater.$)$ Include the function in a short tester program in the file named testsort.py$.($LO: $6\mathrm{.}2)$