docs: def _set_persistent_boot(self, values=[]):
          """Configures a boot from a specific device."""
  
          xml = self._create_dynamic_xml(
              'SET_PERSISTENT_BOOT', 'SERVER_INFO', 'write')
  
          if six.PY2:
              child_iterator = xml.getiterator()
          else:
              child_iterator = xml.iter()
  
          for child in child_iterator:
              for val in values:
                  if child.tag == 'SET_PERSISTENT_BOOT':
                      etree.SubElement(child, 'DEVICE', VALUE=val)
          d = self._request_ilo(xml)
          data = self._parse_output(d)
          return data