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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, validate=False, pretty_print=True, data_path=None):
 """Convert data to JSON Parameters data_path : string If not None, then data is written to a separate file at the specified path. Note that the ``url`` attribute if the data must be set independently for the data to load correctly. Returns ------- string Valid Vega JSON. """

        # TODO: support writing to separate file
        return super(self.__class__, self).to_json(validate=validate,
                                                   pretty_print=pretty_print)