code: func (b *builtinTidbParseTsoSig) evalTime(row chunk.Row) (types.Time, bool, error) {
  	arg, isNull, err := b.args[0].EvalInt(b.ctx, row)
  	if isNull || err != nil || arg <= 0 {
  		return types.Time{}, true, handleInvalidTimeError(b.ctx, err)
  	}
  
  	t := oracle.GetTimeFromTS(uint64(arg))
  	result := types.Time{
  		Time: types.FromGoTime(t),
  		Type: mysql.TypeDatetime,
  		Fsp:  types.MaxFsp,
  	}
  	err = result.ConvertTimeZone(time.Local, b.ctx.GetSessionVars().Location())
  	if err != nil {
  		return types.Time{}, true, err
  	}
  	return result, false, nil
  }
docs: // evalTime evals a builtinTidbParseTsoSig.