current tail next should point to new node

Author: miguelHx

Python/chapter02/2.6 - Palindrome/miguel_2.6_soln.py

@@ -55,6 +55,7 @@ def _append_node(self, n: Node) -> None:
             self.tail = self.head
         else:
             end = n
+            self.tail.next = end
             self.tail = end
         self.size += 1