public void setComment(String comment) {
		checkDeleted();
		if (comment == null)
			comment = "";

		if (!comment.equals(record.getString(BookmarkDBAdapter.COMMENT_COL))) {
			record.setString(BookmarkDBAdapter.COMMENT_COL, comment);
			mgr.bookmarkChanged(this);
		}
	}
Returns bookmark type or null if type has been removed.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/bookmark/BookmarkDB.java