code: def read_xml(self):
          
  
          with reading_ancillary_files(self):
              root = super(ImpactLayerMetadata, self).read_xml()
              if root is not None:
                  self._read_provenance_from_xml(root)
          return root
docs: read metadata from xml and set all the found properties.
  
          :return: the root element of the xml
          :rtype: ElementTree.Element