Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Worksheet/PageSetup.php
public function isPrintAreaSet($index = 0)
    {
        if ($index == 0) {
            return $this->printArea !== null;
        }
        $printAreas = explode(',', $this->printArea);

        return isset($printAreas[$index - 1]);
    }
public function isPrintAreaSet($index = 0)
    {
        if ($index == 0) {
            return $this->printArea !== null;
        }
        $printAreas = explode(',', $this->printArea);

        return isset($printAreas[$index - 1]);
    }
Is print area set?

@param int $index Identifier for a specific print area range if several ranges have been set
Default behaviour, or an index value of 0, will identify whether any print range is set
Otherwise, existence of the range identified by the value of $index will be returned
Print areas are numbered from 1

@return bool