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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, minimal=True):
 """Encode an object as a JSON string. :param bool minimal: Construct a minimal representation of the object (ignore nulls and empty collections) :rtype: str """

        if minimal:
            return json.dumps(self.json_repr(minimal=True), cls=MarathonMinimalJsonEncoder, sort_keys=True)
        else:
            return json.dumps(self.json_repr(), cls=MarathonJsonEncoder, sort_keys=True)