code: def read_xml(self):
          
          if self.xml_uri is None:
              root = self._read_xml_db()
          else:
              root = self._read_xml_file()
          if root is not None:
              for name, path in list(self._standard_properties.items()):
                  value = read_property_from_xml(root, path)
                  if value is not None:
                      # this calls the default setters
                      setattr(self, name, value)
  
          return root
docs: read metadata from xml and set all the found properties.
  
          :return: the root element of the xml
          :rtype: ElementTree.Element