Is it still working ?

[stavigor]

The code

let planWorkTimer = Plan.every(.monday, .tuesday, .wednesday, .thursday, .friday).at("6:49 am").do {
            print("planWorkTimer is start")
}

not print.

[kkkkkkkkNight]

me too

[teodorsorescu]

It won't work if you do not have an available RunLoop (see here).
You either need to specify a queue like:

let planWorkTimer = Plan.every(.monday, .tuesday, .wednesday, .thursday, .friday).at("6:49 am").do(queue: .global()) {
            print("planWorkTimer is start")
}

Or have a RunLoop:

let planWorkTimer = Plan.every(.monday, .tuesday, .wednesday, .thursday, .friday).at("6:49 am").do {
            print("planWorkTimer is start")
}

CFRunLoopRun()