public static GrDocComment setDocComment(@NotNull GrDocCommentOwner owner, @Nullable GrDocComment comment) {
    GrDocComment docComment = owner.getDocComment();

    if (docComment != null) {
      if (comment == null) {
        docComment.delete();
        return null;
      }
      else {
        PsiElement added = docComment.replace(comment);
        assert added instanceof GrDocComment;
        return (GrDocComment)added;
      }
    }
    else {
      if (comment == null) return null;

      PsiElement parent = owner.getParent();

      ASTNode node = owner.getNode();
      parent.getNode().addLeaf(GroovyTokenTypes.mNLS, "\n ", node);

      PsiElement added = parent.addBefore(comment, owner);
      assert added instanceof GrDocComment;

      return (GrDocComment)added;
    }
  }
public static GrDocComment setDocComment(@NotNull GrDocCommentOwner owner, @Nullable GrDocComment comment)