Hack ruby solution
\nclass CombinationIterator\n  attr_accessor :enumerator\n\n=begin\n    :type characters: String\n    :type combination_length: Integer\n=end\n    def initializ
```\nclass CombinationIterator\n  attr_accessor :enumerator\n\n=begin\n    :type characters: String\n    :type combination_length: Integer\n=end\n    def initialize(characters, combination_length)\n        @enumerator = characters.chars.combination(combination_length)\n    end\n\n\n=begin\n    :rtype: String\n=end\n    def next()\n        @enumerator.next.join\n    end\n\n\n=begin\n    :rtype: Boolean\n=end\n    def has_next()\n      enumerator.peek() && true\n    rescue StopIteration\n      false\n    end\n\n\nend\n\n# Your CombinationIterator object will be instantiated and called as such:\n# obj = CombinationIterator.new(characters, combination_length)\n# param_1 = obj.next()\n# param_2 = obj.has_next()\n```
['Ruby']