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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 to_json(self, indent: int=None, ignore_none: bool=True, ignore_empty: bool=False) -> str: """From instance to json string :param indent: Number of indentation :param ignore_none: Properties which is None are excluded if True :param ignore_empty: Properties which is empty are excluded if True :return: Json string Usage: '{"favorites": [{"name": "Apple","names_by_lang": {"de": "Apfel","en": "Apple"}},{"name": "Orange"}],"id": 1,"name": "Tom"}' """

        return util.dump_json(traverse(self, ignore_none, force_value=True, ignore_empty=ignore_empty), indent)