chore: add newline

Author: kangdaia

contains-duplicate/kangdaia.py

@@ -22,4 +22,4 @@ def containsDuplicate(self, nums: list[int]) -> bool:
         """
         if len(nums) <= 1:
             return False
-        return len(nums) != len(set(nums))
+        return len(nums) != len(set(nums))