Please do the following:
- The trailing part of the stacktrace is important. So, change the screenshot / create a code cell with the proper stacktrace. Here’s the community user guide to get started.
- Sharing the complete notebook is discouraged and it can get your account suspended. So, update your text to remove asking for solutions.
- If this topic is related to this reply, don’t create duplicates.
- The concept of callback was covered in course 1 week 2 of this specialization. Please go through the lectures / assignments if things are unclear.