public static string Join <T>([NotNull, InstantHandle] this IEnumerable <T> values) =>
 // ReSharper disable once BuiltInTypeReferenceStyle
 StringClass.Join("", values);
 // ReSharper disable once BuiltInTypeReferenceStyle
 public static bool NotNullNorWhiteSpace([CanBeNull] this string str) => !StringClass.IsNullOrWhiteSpace(str);
 public static string Join <T>([NotNull, InstantHandle] this IEnumerable <T> values, [CanBeNull] string separator) =>
 // ReSharper disable once BuiltInTypeReferenceStyle
 StringClass.Join(separator, values);