docs: def tofile(self, file_):
          """
          Dump all storage data to a file. The file_ argument can be a
          file object or a string that represents a filename. If called
          with a file object, it should be opened in binary mode, and
          the caller is responsible for closing the file.
  
          The method should only be called after the storage device has
          been closed to ensure that the locked flag has been set to
          False.
          """
          close_file = False
          if not hasattr(file_, 'write'):
              file_ = open(file_, 'wb')
              close_file = True
          file_.write(self._f)
          if close_file:
              file_.close()