Good job on implementing your is_sorting function efficiently!
Good job on successfully implementing your selection sort!
Here's some feedback to improve:
I noticed you left out the time complexity for insertion sort. Insertion sort is also an O(n**2) algorithm, since in the worst case, you move the item N spaces to the left (if the last item was the smallest item in the list) AND you are iterating over the list N times.
Try adding a couple more test cases! It may seem intimidating at first, but you've made it past the hard part. Implementation is way tougher than calling these functions and comparing inputs. In the work environment, writing tests will be required. Its a good habit to build :)
Your split_sort_merge is failing tests! Try using print statements and test errors to figure out what's going on or come to office hours.
What was great:
Here's some feedback to improve: