/*
 * Copyright (c) 2023 - 2024 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

class Residence {
    numberOfRooms: int = 1;
}

class Person {
    residence: Residence = new Residence();
}

function hasResidence(person: Person | null) : boolean {
    return person?.residence != null;
}

function main(): void {
    let john = null;
    assert(hasResidence(john) == false);
}