code: def _check_root_tag(self, root):
          
          supported = self.supported_tags()
          if root.tag in supported:
              return
  
          error = "Document root element ({0}) not one of ({1})"
          raise UnsupportedRootElementError(
              message=error.format(root.tag, supported),
              expected=supported,
              found=root.tag,
          )
docs: Check that the XML element tree has a supported root element.
  
          Args:
              root (etree.Element)
  
          Raises:
              UnsupportedRootElementError