code: def _structmap(self):
          
          structmap = etree.Element(
              utils.lxmlns("mets") + "structMap",
              TYPE="physical",
              # TODO Add ability for multiple structMaps
              ID="structMap_1",
              # TODO don't hardcode this
              LABEL="Archivematica default",
          )
          for item in self._root_elements:
              child = item.serialize_structmap(recurse=True)
              if child is not None:
                  structmap.append(child)
  
          return structmap
docs: Returns structMap element for all files.