public function testCachingBug(): void         
{                                           
    $old = ['a'];                           
    $new = ['a', 'b', 'c'];                 
                                            
    $this->sm->setSeq1($old)->setSeq2($new);
                                            
    $old = ['a', 'b'];                      
    $new = ['a', 'b', 'c'];                 
                                            
    $this->sm->setSeq1($old)->setSeq2($new);

    // Throws ErrorException: "Undefined array key 1" 
    $this->sm->getOpcodes();                
}