protected PsiElement @NotNull [] getChildren(PsiElement @Nullable ... children) {
    if (children == null) {
      return PsiElement.EMPTY_ARRAY;
    }

    List<PsiElement> list = new ArrayList<>(children.length);
    for (PsiElement child : children) {
      if (child != null) {
        list.add(child);
      }
    }
    return PsiUtilCore.toPsiElementArray(list);
  }
protected PsiElement @NotNull [] getChildren(PsiElement @Nullable ... children)