let dog = ["id": 1, "name": "アレキサンダー", "owner": "ニーナ", "age": 10, "children": [["id": 2, "name": "ポチ", "owner": "ニーナ", "age": 3, "children": NSNull()], ["id": 3, "name": "チビ", "owner": "ニーナ", "age": 2, "children": NSNull()]]] (lldb) po dog ▿ 5 elements ▿ [0] : 2 elements - .0 : "owner" - .1 : ニーナ ▿ [1] : 2 elements - .0 : "age" ▿ [2] : 2 elements - .0 : "id" ▿ [3] : 2 elements - .0 : "children" ▿