@Nullable
  public static PsiElement skipParentheses(@Nullable PsiElement element, boolean up) {
    if (element == null) return null;
    if (up) {
      PsiElement parent;
      while ((parent = element.getParent()) instanceof GrParenthesizedExpression) {
        element = parent;
      }
    }
    else {
      while (element instanceof GrParenthesizedExpression) {
        element = ((GrParenthesizedExpression)element).getOperand();
      }
    }
    return element;
  }
@Nullable
  public static PsiElement skipParentheses(@Nullable PsiElement element, boolean up)