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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 get_different_page(self, request, page):
 """ Returns a url that preserves the current querystring while changing the page requested to `page`. """


        if page:
            qs = request.GET.copy()
            qs['page'] = page
            return "%s?%s" % (request.path_info, qs.urlencode())
        return None