code: def to_file(self, filepath):
          
          lfd = LockedFD(filepath)
          assure_directory_exists(filepath, is_file=True)
  
          fp = lfd.open(write=True, stream=True)
          try:
              self._serialize(fp)
              lfd.commit()
          except Exception:
              # on failure it rolls back automatically, but we make it clear
              lfd.rollback()
              raise
docs: Write the contents of the reflog instance to a file at the given filepath.
          :param filepath: path to file, parent directories are assumed to exist