def __str__(self):
    content = ('RESTORE_OPTIMISTIC: %s\nRESTORE_CHECKPOINT_FILE: %s' % (self._restore_optimistic, self.restore_ckpt_file))
    return content
def __str__(self):
    content = ('RESTORE_OPTIMISTIC: %s\nRESTORE_CHECKPOINT_FILE: %s' % (self._restore_optimistic, self.restore_ckpt_file))
    return content