code: function compareTimeZones(a, b) {
      if (typeof a !== 'string' || typeof b !== 'string') {
        return NaN;
      }
  
      return normalizeIso8601TimeZone(a) - normalizeIso8601TimeZone(b);
    }
docs: Compares the given time zone representations. Returns a negative number if a is less than b, a positive number if a is greater than b, or zero if a and b are equal.