1<?php
2class Calculator
3{
4    /**
5     * @assert (0, 0) == 0
6     * @assert (0, 1) == 1
7     * @assert (1, 0) == 1
8     * @assert (1, 1) == 2
9     */
10    public function add($a, $b)
11    {
12        return $a + $b;
13    }
14}
15