private static function validExcelObj($excelObj=NULL)
    {
        if (is_object($excelObj)) {

            return $excelObj;
        } 
        elseif (is_object(self::$_objSpreadsheet)) {

            return self::$_objSpreadsheet;
        } 
        else {
            
            throw new Exception("Invalid or empty PhpSpreadsheet Object", 400);
        }
    }
private static function validExcelObj($excelObj=NULL)
    {
        if (is_object($excelObj)) {

            return $excelObj;
        } 
        elseif (is_object(self::$_objSpreadsheet)) {

            return self::$_objSpreadsheet;
        } 
        else {
            
            throw new Exception("Invalid or empty PhpSpreadsheet Object", 400);
        }
    }
private static function validExcelObj ( $ excelObj = NULL ) { if ( is_object ( $ excelObj ) ) { return $ excelObj ; } elseif ( is_object ( self :: $ _objSpreadsheet ) ) { return self :: $ _objSpreadsheet ; } else { throw new Exception ( "Invalid or empty PhpSpreadsheet Object" , 400 ) ; } }
Validate and return the selected PhpSpreadsheet Object

@param object $excelObj PhpSpreadsheet Object
@return object Cached object or given object
Validate and return the selected PhpSpreadsheet Object