Example code for article about ArgumentParser - Runtime validation

RuntimeValidation.Swift

mutating func run() throws {
    let filePathWithExtension = "\(filePath)\(fileExtension)"
    // 1
    do {
        try note.write(toFile: filePathWithExtension, atomically: true, encoding: .utf8)
    } catch {
        // 2
        throw RuntimeError("Couldn't write to `\(filePath)`!")
    }
}