src/Datastructure/Stackqueue/FixedQueue.php
protected function isValid(): bool {
        $parent = parent::isValid();
        $maxSize = parent::size() < $this->maxSize;
        return $parent && $maxSize;
    }
protected function isValid(): bool {
        $parent = parent::isValid();
        $maxSize = parent::size() < $this->maxSize;
        return $parent && $maxSize;
    }
protected function isValid ( ) : bool { $ parent = parent :: isValid ( ) ; $ maxSize = parent :: size ( ) < $ this -> maxSize ; return $ parent && $ maxSize ; }
returns whether the element is valid or not.
Checks among other things also the number of elements

@return bool
returns whether the element is valid or not . Checks among other things also the number of elements