code: func (t *Time) ConvertTimeZone(from, to *gotime.Location) error {
  	if !t.IsZero() {
  		raw, err := t.Time.GoTime(from)
  		if err != nil {
  			return errors.Trace(err)
  		}
  		converted := raw.In(to)
  		t.Time = FromGoTime(converted)
  	}
  	return nil
  }
docs: // ConvertTimeZone converts the time value from one timezone to another.
  // The input time should be a valid timestamp.