public function extract()
    {
        if (! $this->valid()) {
            return false;
        }
        $value = $this->current();
        $this->nextAndRemove();
        return $value;
    }
public function extract()
    {
        if (! $this->valid()) {
            return false;
        }
        $value = $this->current();
        $this->nextAndRemove();
        return $value;
    }
public function extract ( ) { if ( ! $ this -> valid ( ) ) { return false ; } $ value = $ this -> current ( ) ; $ this -> nextAndRemove ( ) ; return $ value ; }
Extract an element in the queue according to the priority and the
order of insertion

@return mixed
Extract an element in the queue according to the priority and the order of insertion