code: def flush(self, fsync=False):
          
          if self._handle is not None:
              self._handle.flush()
              if fsync:
                  try:
                      os.fsync(self._handle.fileno())
                  except OSError:
                      pass
docs: Force all buffered modifications to be written to disk.
  
          Parameters
          ----------
          fsync : bool (default False)
            call ``os.fsync()`` on the file handle to force writing to disk.
  
          Notes
          -----
          Without ``fsync=True``, flushing may not guarantee that the OS writes
          to disk. With fsync, the operation will block until the OS claims the
          file has been written; however, other caching layers may still
          interfere.