code: def project_closed(self, project):
          
  
          yield from super().project_closed(project)
          hdd_files_to_close = yield from self._find_inaccessible_hdd_files()
          for hdd_file in hdd_files_to_close:
              log.info("Closing VirtualBox VM disk file {}".format(os.path.basename(hdd_file)))
              try:
                  yield from self.execute("closemedium", ["disk", hdd_file])
              except VirtualBoxError as e:
                  log.warning("Could not close VirtualBox VM disk file {}: {}".format(os.path.basename(hdd_file), e))
                  continue
docs: Called when a project is closed.
  
          :param project: Project instance