clapslock

def removeSpacesAndSpecialChars(inputText):

    whitelist = set('abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')

    answer = ''.join(filter(whitelist.__contains__, inputText))
    answer = answer.lower()
    return answer

clapslock

private func getRootViewController() -> UIViewController? {
    var rootViewController = UIApplication.shared.keyWindow?.rootViewController
    if let navigationController = rootViewController as? UINavigationController {
        rootViewController = navigationController.viewControllers.first
    }
    if let tabBarController = rootViewController as? UITabBarController {
        rootViewController = tabBarController.selectedViewController
    }
    return rootViewController
}