Code example for the article "Swift, Plist and Two Smoking Scripts" https://medium.com/rosberryapps/swift-plist-and-two-smoking-scripts-94bb54cbeded

swift-build-phase-scripts-4.swift

guard let productSettings = NSDictionary(contentsOfFile: productSettingsPath) else {
    exit(1)
}
for key in keys {
    guard let value = productSettings[key] as? String else {
        // Missing key
        exit(1)
    }
    if value.isEmpty {
        // Empty description
        exit(1)
    }
}