modified 541. Can be more pythonic.

problems/0541.反转字符串II.md

@@ -204,8 +204,23 @@ class Solution:
         return ''.join(res)
 ```
 
+Python3 (v2):
+
+```python
+class Solution:
+    def reverseStr(self, s: str, k: int) -> str:
+        # Two pointers. Another is inside the loop.
+        p = 0
+        while p < len(s):
+            p2 = p + k
+            # Written in this could be more pythonic.
+            s = s[:p] + s[p: p2][::-1] + s[p2:]
+            p = p + 2 * k
+        return s
+```
 
 Go：
+
 ```go
 func reverseStr(s string, k int) string {
     ss := []byte(s)