Update assignment

inversions.py

@@ -34,6 +34,6 @@ def _inversions(xs):
     total += left + right
     return (count + lcount + rcount), total
 
-def inversions(xs):
+def num_inversions(xs):
     count, _ = _inversions(xs)
     return count

msort.py

@@ -1,9 +1,9 @@
-def msort(xs):
+def mergesort(xs):
     if len(xs) < 2: return xs
 
     leng = len(xs) // 2
-    left = msort(xs[:leng])
-    right = msort(xs[leng:])
+    left = mergesort(xs[:leng])
+    right = mergesort(xs[leng:])
 
     # Reversing is O(n), but so is copying, so
     # this does not worsen complexity.