Creating an object which takes multiples values for a single key in swift

How can I Have multiple value with same key?

{
    attribute[city][values][value][]:123
    attribute[city][values][value][]:156
    attribute[city][must_have]:1
    attribute[city][values][value][]:1
    attribute[make][must_have]:1
    attribute[make][values][value][]:45
     attribute[make][values][value][]:87
}

should I create own object type? In case of yes how to create such strucure?