code: private static Pair pair(String string, char separator)
    {
      int separatorIndex = string.indexOf(separator);
      if(separatorIndex == -1) {
        throw new BugError("Missing pair separator. Cannot initialize pair instance.");
      }
      final String first = string.substring(0, separatorIndex).trim();
      final String second = string.substring(separatorIndex + 1).trim();
      return new Pair(first, second);
    }
docs: Split string value using given separator and return initialized pair instance. Pair values are trimmed for spaces
  so that this method eliminates spaces around separator and around string value. For example, " john : doe " will
  return Pair("john", "doe").
  
  @param string string value,
  @param separator pair components separator.
  @return newly create pair instance.
  @throws BugError if separator not found.