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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_xml_string(self):
 """ Exports the element in XML format. :returns: element in XML format. :rtype: str """


        self.update_xml_element()
        xml = self.xml_element

        return etree.tostring(xml, pretty_print=True).decode('utf-8')