class FakeRule extends Rule {
    @Override public String getId() { return "FAKE-RULE-FOR-FILTER"; }
    @Override public String getDescription() { return "<none>"; }
    @Override public RuleMatch[] match(AnalyzedSentence sentence) throws IOException { return new RuleMatch[0]; }
  }

  protected String getRequired(String key, Map<String, String> map) {<FILL_FUNCTION_BODY>

    String result = map.get(key);
    if (result == null) {
      throw new IllegalArgumentException("Missing key '" + key + "'");
    }
    return result;
  
<no_super_class>