anchor.diff:                  throw new FailedPredicateException(input, "python_style_dict", "JSONException: " + err.getMessage());
               }
           }
  -        (COMMA p=key_value_pair[true]
  +        (COMMA p=key_value_pair[KeyType.STRING_LITERAL]
               {
                   try {
                       $json.put($p.key, $p.val);
  
positive.code: }
  
  @parser::members {
  
      private static final int DEFAULT_REQUEST_OFFSET = 0;
      private static final int DEFAULT_REQUEST_COUNT = 10;
  
negative.code:         )* RPAR
      ;
  
  key_value_pair[KeyType keyType] returns [String key, Object val]
  scope {
      KeyType type
  }
  @init {
      $key_value_pair::type = keyType;
  }
      :   ( { $key_value_pair::type == KeyType.STRING_LITERAL ||
              $key_value_pair::type == KeyType.STRING_LITERAL_AND_IDENT}?=> STRING_LITERAL
          | { $key_value_pair::type == KeyType.IDENT ||
              $key_value_pair::type == KeyType.STRING_LITERAL_AND_IDENT}?=> IDENT
          )
          COLON (v=value | vs=python_style_list | vd=python_style_dict)
          {
  