{
    "number1": { "number_between": [10, 20] },
    "number2": { "number_between": [20, 30] },
    "number3": [ { "number_between": [-1, 1] } ],
    "number4": [ { "number_between": [-10, 10] } ],
    "empty_field": { "number_between": [10, 20] }
}