Yosymfony\Spress\Core\Support\ArrayWrapper::flatten PHP Method

    public function flatten()
    {
        $array = [];
        array_walk_recursive($this->array, function ($element) use(&$array) {
            $array[] = $element;
        });
        return $array;
    }

 public function testFlatten()
 {
     $a = new ArrayWrapper(['item 1' => [1, 2, 3], 'item 2' => [4, 5, 6]]);
     $arraySingleLevel = $a->flatten();
     $this->assertTrue(is_array($arraySingleLevel));
     $this->assertCount(6, $arraySingleLevel);
     $this->assertTrue($arraySingleLevel === [1, 2, 3, 4, 5, 6]);
 }