Write merge_sorted(a, b) that merges two already-sorted lists into one sorted list without calling sort/sorted.
merge_sorted([1, 4, 7], [2, 3, 9]) → [1, 2, 3, 4, 7, 9]
merge_sorted([], [1, 2]) → [1, 2]
Submit runs 5 tests, including hidden edge cases.
Run your code to see the output here.