code: def to_etree(self):
          
          attribs = {
              '{{{pre}}}type'.format(pre=NAMESPACES['xsi']): self.xsi_type,
              'namespace': self.namespace, 'name': self.name,
              'value': self.hexvalue, 'valueString': self.value}
          non_empty_attribs = {key: val for (key, val) in attribs.items()
                               if val is not None}
          E = ElementMaker()
          return E('labels', non_empty_attribs)
docs: creates an etree element of a ``SaltLabel`` that mimicks a SaltXMI
          <labels> element