@Override
  public ASTNode findChildByRole(int role) {
    LOG.assertTrue(ChildRole.isUnique(role));
    switch (role) {
      case ChildRole.LPARENTH:
        TreeElement firstNode = getFirstChildNode();
        return firstNode.getElementType() == LPARENTH ? firstNode : null;

      case ChildRole.RPARENTH:
        TreeElement lastNode = getLastChildNode();
        return lastNode.getElementType() == RPARENTH ? lastNode : null;

      default:
        return null;
    }
  }
@Override
  public ASTNode findChildByRole(int role)