public function allFills(Spreadsheet $spreadsheet)
    {
        // Get an array of unique fills
        $aFills = [];

        // Two first fills are predefined
        $fill0 = new Fill();
        $fill0->setFillType(Fill::FILL_NONE);
        $aFills[] = $fill0;

        $fill1 = new Fill();
        $fill1->setFillType(Fill::FILL_PATTERN_GRAY125);
        $aFills[] = $fill1;
        // The remaining fills
        $aStyles = $this->allStyles($spreadsheet);
        /** @var \PhpOffice\PhpSpreadsheet\Style\Style $style */
        foreach ($aStyles as $style) {
            if (!isset($aFills[$style->getFill()->getHashCode()])) {
                $aFills[$style->getFill()->getHashCode()] = $style->getFill();
            }
        }

        return $aFills;
    }