docs: def root(self):
          """
          TODO(rdelinger) rename this as to_xml or something similar
          """
          self.xml_root = ElementTree.Element('interface')
          self.xml_root.set('type', self.type)
          if self.mac is not None:
              mac = ElementTree.SubElement(self.xml_root, 'mac')
              mac.set('address', self.mac)
          _source = ElementTree.SubElement(self.xml_root, 'source')
          _source.set(self.type, self.source)
          _model = ElementTree.SubElement(self.xml_root, 'model')
          _model.set('type', self.model)
          return self.xml_root