PHP SplPriorityQueue isEmpty() Function

<?php

// Declare empty class
class priorityQueue extends SplPriorityQueue {
}

// Create an object of priority queue
$obj = new priorityQueue();

// Use isEmpty() function to check
// priority queue is empty or not
var_dump($obj->isEmpty());

?>

<?php

// Declare a class
class priorityQueue extends SplPriorityQueue {
    
    // Compare function to compare priority
    // queue elements
    public function compare($p1, $p2) {
        if ($p1 === $p2) return 0;
        return $p1 < $p2 ? -1 : 1;
    }
}

// Create an object of priority queue
$obj = new priorityQueue();

// Insert elements into the queue
$obj->insert("Geeks",2);
$obj->insert("GFG",1);
$obj->insert("G4G",3);
$obj->insert('G',4);

// Use isEmpty() function to check
// priority queue is empty or not
var_dump($obj->isEmpty());

?>