code: def close(self):
          
          if self.file is None:
              return
  
          # Close the pickle file.
          self.file.close()
          self.file = None
  
          for f in self.mark_for_delete:
              error = [False]
  
              def register_error(*args):
                  error[0] = True
  
              _shutil.rmtree(f, onerror = register_error)
  
              if error[0]:
                  _atexit.register(_shutil.rmtree, f, ignore_errors=True)
docs: Close the pickle file, and the zip archive file. The single zip archive
          file can now be shipped around to be loaded by the unpickler.