public function allFonts(Spreadsheet $spreadsheet)
    {
        // Get an array of unique fonts
        $aFonts = [];
        $aStyles = $this->allStyles($spreadsheet);

        /** @var \PhpOffice\PhpSpreadsheet\Style\Style $style */
        foreach ($aStyles as $style) {
            if (!isset($aFonts[$style->getFont()->getHashCode()])) {
                $aFonts[$style->getFont()->getHashCode()] = $style->getFont();
            }
        }

        return $aFonts;
    }