code: func (dd *xlsxCellDataValidation) SetInFileList(sheet string, x1, y1, x2, y2 int) error {
  	start := GetCellIDStringFromCoordsWithFixed(x1, y1, true, true)
  	if y2 < 0 {
  		y2 = Excel2006MaxRowIndex
  	}
  
  	end := GetCellIDStringFromCoordsWithFixed(x2, y2, true, true)
  	// Escape single quotes in the file name.
  	// Single quotes are escaped by replacing them with two single quotes.
  	sheet = strings.Replace(sheet, "'", "''", -1)
  	formula := "'" + sheet + "'" + externalSheetBangChar + start + cellRangeChar + end
  	dd.Formula1 = formula
  	dd.Type = convDataValidationType(dataValidationTypeList)
  	return nil
  }
docs: // SetInFileList is like SetDropList, excel that instead of having a hard coded list,
  // a reference to a part of the file is accepted and the list is automatically taken from there.
  // Setting y2 to -1 will select all the way to the end of the column. Selecting to the end of the
  // column will cause Google Sheets to spin indefinitely while trying to load the possible drop down
  // values (more than 5 minutes).
  // List validations do not work in Apple Numbers.