Python super-simple and easy solution
\nclass CombinationIterator:\n    def __init__(self, characters: str, combinationLength: int):\n        self.allCombinations = list(combinations(characters, com
```\nclass CombinationIterator:\n    def __init__(self, characters: str, combinationLength: int):\n        self.allCombinations = list(combinations(characters, combinationLength))\n        self.count = 0\n\n    def next(self) -> str:\n        self.count += 1\n        return "".join(self.allCombinations[self.count-1])\n        \n    def hasNext(self) -> bool:\n        return self.count < len(self.allCombinations)\n\n```
['Python3']