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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def dict2str(self, d: Dict, joiner: str) -> str: """ Convert dict to str as input for tokenizer Args: d (dict):
 dict for converting joiner (str):
 join the elements using this string to separate them. Returns: the value of the dict as a string """

        result = str()
        for key in d:
            result = result + str(key) + " : "
            if isinstance(d[key], list):
                result = result + self.list2str(d[key], joiner) + joiner
            elif isinstance(d[key], dict):
                result = result + self.dict2str(d[key], joiner) + joiner
            elif d[key]:
                result = result + str(d[key]) + joiner
        return result