<?php
$a = new \Ds\Deque([1, 2, 3]);
$b = $a->copy();
$b->push(4);
print_r($a);
print_r($b);
?>
The above example will output
something similar to:
Ds\Deque Object
(
[0] => 1
[1] => 2
[2] => 3
)
Ds\Deque Object
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
)