@Contract(pure = true)
  public static int comparePairs(@Nullable String s1, @Nullable String t1, @Nullable String s2, @Nullable String t2, boolean ignoreCase) {
    int compare = compare(s1, s2, ignoreCase);
    return compare != 0 ? compare : compare(t1, t2, ignoreCase);
  }
@Contract(pure = true)
  public static int comparePairs(@Nullable String s1, @Nullable String t1, @Nullable String s2, @Nullable String t2, boolean ignoreCase)