Class.swift

class Class {
    let id: Int

    init(id: Int) {
        self.id = id
    }
}

class Schedule {
    let `class`: Class

    init(class: Class) {
        self.class = `class`
    }
}

let `class` = Class(id: 1)
let schedule = Schedule(class: `class`)

print(schedule.`class`.id)