cant figure out qs in python

python/quicksort.py

@@ -0,0 +1,20 @@
+def partition(arr, lo, hi):
+    pivot_value = arr[hi]
+    current_index = lo - 1
+
+    for i in range(lo, hi):
+        if arr[i] <= pivot_value:
+            current_index += 1
+            arr[current_index], arr[i] = arr[i], arr[current_index]
+    current_index += 1
+    arr[hi] = arr[current_index]
+    arr[current_index] = pivot_value
+    return current_index
+
+def quicksort(arr, lo, hi):
+    if lo < hi:
+        part = partition(arr, lo, hi)
+        partition(arr, lo, part - 1)
+        partition(arr, part + 1, hi)
+
+