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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 make_json_serializable(doc: Dict):
 """ Make the document JSON serializable. This is a poor man's implementation that handles dates and nothing else. This method modifies the given document in place. Args: doc: A Python Dictionary, typically a CDR object. Returns: None """

        for k, v in doc.items():
            if isinstance(v, datetime.date):
                doc[k] = v.strftime("%Y-%m-%d")
            elif isinstance(v, datetime.datetime):
                doc[k] = v.isoformat()