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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 reduce_sort(self, js_cmp=None, options=None):
 """ Adds the Javascript built-in ``Riak.reduceSort`` to the query as a reduce phase. :param js_cmp: A Javascript comparator function as specified by Array.sort() :type js_cmp: string :param options: phase options, containing 'language', 'keep' flag, and/or 'arg'. :type options: dict """

        if options is None:
            options = dict()

        if js_cmp:
            options['arg'] = js_cmp

        return self.reduce("Riak.reduceSort", options=options)