{
    "city1": { "one_of": [["Moscow", "Kiev" ]] },
    "city2": [{ "one_of": [["Moscow", "Kiev" ]] }],
    "city3": { "one_of": ["Moscow", "Kiev"] },
    "number1": { "one_of": [1, 2] },
    "number2": { "one_of": ["1", "2"] },
    "number3": { "one_of": 1.2 },
    "boolean": { "one_of": [true, false] },
    "empty_city": { "one_of": [["Moscow", "Kiev" ]] }
}