{
    "address": [ "required", { "nested_object": {
        "country": ["required", { "one_of": [["Ukraine", "USA"]] } ],
        "zip": "positive_integer",
        "street": "required",
        "building": ["required",  "positive_integer" ]
    } } ],
    "address2": { "nested_object": { "country": "required" } }
}