public boolean addCard(Card c) {
                            ArrayList<String> extKeywords = new ArrayList<String>(Arrays.asList(extrinsicKeywords));
                            for (String s : extKeywords) {

                                // We want to give a new keyword
                                if (!c.hasKeyword(s))
                                    return true;
                            }
                            //no new keywords:
                            return false;
                        }