code: protected boolean hasI18nKey(final String aMessageKey) {
          return myBundle != null && aMessageKey != null && myBundle.containsKey(aMessageKey);
      }
docs: Returns true if this I18N object contains the requested I18N key; else, false.
  
  @param aMessageKey A key to check to see if it exists
  @return True if the key exists; else, false