public static class Guard
{
	public static void NotNull<T>(string argumentName, T value)
		where T : class
	{
		if (value == null)
			throw new ArgumentNullException(argumentName);
	}

	public static void NotEmpty(string argumentName, string value)
	{
		if (String.IsNullOrWhiteSpace(value))
			throw new ArgumentException("Non-empty string expected", argumentName);
	}
}