private static boolean isKeyValue(Block maybeKey, Block maybeValue) {
    if (!(maybeKey instanceof PropertyBlock) ||
        !PropertiesTokenTypes.KEY_CHARACTERS.equals(((PropertyBlock)maybeKey).getNode().getElementType())) {
      return false;
    }
    return maybeValue instanceof PropertyBlock &&
           PropertiesTokenTypes.VALUE_CHARACTERS.equals(((PropertyBlock)maybeValue).getNode().getElementType());
  }
private static boolean isKeyValue(Block maybeKey, Block maybeValue)