person: None
├─ name: John Doe
├─ age: 35u8
├─ address: None
│  ├─ street: 123 Main St
│  ├─ city: Anytown
│  └─ zip: 12345u16
├─ phones: None
│  ├─ home: 555-1234
│  └─ work: 555-5678
└─ account: None
   ├─ number: 9876543210123456
   └─ balance: 5000i32
