Possible way to detect sim card detection in ios?

Question

I have a iphone app that has the capability to send messages. I want to alert user when sim card is not available in iphone. So i tried below three function to check sim car

Answer 1

Swift 4+

var isSimCardAvailable: Bool {

    let info = CTTelephonyNetworkInfo()
    if let carrier = info.subscriberCellularProvider {
        if let code = carrier.mobileNetworkCode {
            if !code.isEmpty {
                return true
            }
        }
    }
    return false
}