Functional\Tests\ReduceTest::functionalCallback PHP Метод

    public function functionalCallback($value, $key, $collection, $returnValue)
    {
        $this->assertContains($value, $this->currentCollection);
        $this->assertTrue(isset($this->currentCollection[$key]));
        $this->assertSame($collection, $this->currentCollection);
        $ret = $key . ':' . $value;
        if ($returnValue) {
            return $returnValue . ',' . $ret;
        }
        return $ret;
    }