[WIP] Kaf notifications

| Q                    | A
| -------------------- | ---
| Bug fix?             |
| New feature?         | Y
| BC breaks?           |
| CI currently passes? |
| Tests pass?          |
| Scenarios pass?      |
| Checkstyle issues?*  |
| PMD issues?**        |
| Changelog updated?   |
| Fixed tickets        |
| Doc PR               |
I would have do the test with a is_object, as it is more robust. If a numeric is provided for example, the variable will be considered as an object and method called upon it, which will fail. If you test on is_object, the numeric can be automatically converted to string.