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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(self, xml_declaration=True):
 """ Return the contents of this verb as an XML string :param bool xml_declaration: Include the XML declaration. Defaults to True """

        xml = ET.tostring(self.xml()).decode('utf-8')
        return '<?xml version="1.0" encoding="UTF-8"?>{}'.format(xml) if xml_declaration else xml