diff --git a/solutions/python3/2.py b/solutions/python3/2.py
index 7354952..f81172f 100644
--- a/solutions/python3/2.py
+++ b/solutions/python3/2.py
@@ -1,8 +1,8 @@
-# Definition for singly-linked list.
-# class ListNode:
-#     def __init__(self, x):
-#         self.val = x
-#         self.next = None
+#Definition for singly-linked list.
+class ListNode:
+    def __init__(self, x):
+        self.val = x
+        self.next = None
 
 class Solution:
     def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode: