<?php
$stack = new \Ds\Stack();
$stack->push("a");
$stack->push("b");
$stack->push("c", "d");
$stack->push(...["e", "f"]);
print_r($stack);
?>
The above example will output
something similar to:
Ds\Stack Object
(
[0] => a
[1] => b
[2] => c
[3] => d
[4] => e
[5] => f
)