code: public static String getLanguageCode(String wikimediaLanguageCode) {
  		if (LANGUAGE_CODES.containsKey(wikimediaLanguageCode)) {
  			return LANGUAGE_CODES.get(wikimediaLanguageCode);
  		} else {
  			throw new IllegalArgumentException("Unknown Wikimedia language \""
  					+ wikimediaLanguageCode + "\".");
  		}
  
  	}
docs: Get a <a href="http://www.rfc-editor.org/rfc/bcp/bcp47.txt">BCP 47</a>
  language code for the given Wikimedia language code.
  
  @param wikimediaLanguageCode
  the language code as used by Wikimedia
  @return the BCP 47 language code
  @throws IllegalArgumentException
  if the given Wikimedia language code is not known. In
  particular, the method will not assume that unknown codes
  agree with BCP 47 by default (since they have no reason to do
  this).