@Nullable
  public static PsiElement getChildByFilter(@NotNull PsiElement element, @NotNull TokenSet filter, int number) {
    final ASTNode node = element.getNode();
    if (node != null) {
      final ASTNode[] children = node.getChildren(filter);
      return (0 <= number && number < children.length) ? children[number].getPsi() : null;
    }
    return null;
  }
@Nullable
  public static PsiElement getChildByFilter(@NotNull PsiElement element, @NotNull TokenSet filter, int number)