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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 uniq(self, isSorted=False, iterator=None):
 """ Produce a duplicate-free version of the array. If the array has already been sorted, you have the option of using a faster algorithm. Aliased as `unique`. """

        ns = self.Namespace()
        ns.results = []
        ns.array = self.obj
        initial = self.obj
        if iterator is not None:
            initial = _(ns.array).map(iterator)

        def by(memo, value, index):
            if ((_.last(memo) != value or
                 not len(memo)) if isSorted else not _.include(memo, value)):
                memo.append(value)
                ns.results.append(ns.array[index])

            return memo

        ret = _.reduce(initial, by)
        return self._wrap(ret)