example\FunctorCollectionTest::test_it_should_return_new_map PHP Method

    public function test_it_should_return_new_map()
    {
        $collection = Listt::of([['id' => 1, 'name' => 'One'], ['id' => 2, 'name' => 'Two'], ['id' => 3, 'name' => 'Three']]);
        $result = $collection->map(function ($a) {
            return $a['id'] + 1;
        });
        $this->assertEquals(Listt::of([2, 3, 4]), $result);
    }