docs: @Pure
  	public static String join(MACNumber... addresses) {
  		if ((addresses == null) || (addresses.length == 0)) {
  			return null;
  		}
  		final StringBuilder buf = new StringBuilder();
  		for (final MACNumber number : addresses) {
  			if (buf.length() > 0) {
  				buf.append(MACNUMBER_SEPARATOR);
  			}
  			buf.append(number);
  		}
  		return buf.toString();
  	}