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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_scan_results_xml(self, scan_id, pop_res):
 """ Gets scan_id scan's results in XML format. @return: String of scan results in xml. """

        results = Element('results')
        for result in self.scan_collection.results_iterator(scan_id, pop_res):
            results.append(get_result_xml(result))

        logger.info('Returning %d results', len(results))
        return results