Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Worksheet/Worksheet.php
public function setBreak($pCoordinate, $pBreak)
    {
        // Uppercase coordinate
        $pCoordinate = strtoupper($pCoordinate);

        if ($pCoordinate != '') {
            if ($pBreak == self::BREAK_NONE) {
                if (isset($this->breaks[$pCoordinate])) {
                    unset($this->breaks[$pCoordinate]);
                }
            } else {
                $this->breaks[$pCoordinate] = $pBreak;
            }
        } else {
            throw new Exception('No cell coordinate specified.');
        }

        return $this;
    }
public function setBreak($pCoordinate, $pBreak)
    {
        // Uppercase coordinate
        $pCoordinate = strtoupper($pCoordinate);

        if ($pCoordinate != '') {
            if ($pBreak == self::BREAK_NONE) {
                if (isset($this->breaks[$pCoordinate])) {
                    unset($this->breaks[$pCoordinate]);
                }
            } else {
                $this->breaks[$pCoordinate] = $pBreak;
            }
        } else {
            throw new Exception('No cell coordinate specified.');
        }

        return $this;
    }
Set break on a cell.

@param string $pCoordinate Cell coordinate (e.g. A1)
@param int $pBreak Break type (type of Worksheet::BREAK_*)

@throws Exception

@return Worksheet