[Python] ugly code
\nclass Solution:\n    def modifyString(self, s: str) -> str:\n        a = list(s)\n\n        for i in range(len(a)):\n            if a[i] != \'?\':\n          
```\nclass Solution:\n    def modifyString(self, s: str) -> str:\n        a = list(s)\n\n        for i in range(len(a)):\n            if a[i] != \'?\':\n                continue\n\n            used = set()\n            if i > 0:\n                used.add(a[i - 1])\n            if i + 1 < len(s):\n                used.add(a[i + 1])\n\n            a[i] = next(iter(set(string.ascii_lowercase) - set(used)))\n\n        return \'\'.join(a)\n```
['Python']