sheet = null; if ($this->spreadsheet !== null) { $this->spreadsheet->disconnectWorksheets(); $this->spreadsheet = null; } } protected function getSpreadsheet(): Spreadsheet { if ($this->spreadsheet !== null) { return $this->spreadsheet; } $this->spreadsheet = new Spreadsheet(); return $this->spreadsheet; } protected function getSheet(): Worksheet { if ($this->sheet !== null) { return $this->sheet; } $this->sheet = $this->getSpreadsheet()->getActiveSheet(); return $this->sheet; } }