public function allConditionalStyles(Spreadsheet $spreadsheet)
    {
        // Get an array of all styles
        $aStyles = [];

        $sheetCount = $spreadsheet->getSheetCount();
        for ($i = 0; $i < $sheetCount; ++$i) {
            foreach ($spreadsheet->getSheet($i)->getConditionalStylesCollection() as $conditionalStyles) {
                foreach ($conditionalStyles as $conditionalStyle) {
                    $aStyles[] = $conditionalStyle;
                }
            }
        }

        return $aStyles;
    }