[Python3] simulation
Please pull this commit for solutions of weekly 281. \n\n\nclass Solution:\n    def mergeNodes(self, head: Optional[ListNode]) -> Optional[ListNode]:\n        d
Please pull this [commit](https://github.com/gaosanyong/leetcode/commit/793daa0aab0733bfadd4041fdaa6f8bdd38fe229) for solutions of weekly 281. \n\n```\nclass Solution:\n    def mergeNodes(self, head: Optional[ListNode]) -> Optional[ListNode]:\n        dummy = node = ListNode()\n        chunk = head\n        while chunk: \n            chunk = chunk.next \n            sm = 0 \n            while chunk and chunk.val: \n                sm += chunk.val \n                chunk = chunk.next \n            if sm: node.next = node = ListNode(sm)\n        return dummy.next \n```
['Python3']