Cant get geometry script to work on blender 3.5

I'm trying out Geometry Script, but I can't get it to work.
when I run the script for Repeat Grid.py its not making node tree correctly like in image in the documentation, not sure what is wrong
It looks like this - https://i.imgur.com/7jXvyIH.png

am I missing something?
it also gives this error when I press Run Script
```
Python: Traceback (most recent call last):
File "C:\Users\Positivity\Desktop\GN_Test01.blend\Repeat Grid.py", line 4, in
File "C:\Users\Positivity\AppData\Roaming\Blender Foundation\Blender\3.5\scripts\addons\geometry-script-main\api\tree.py", line 98, in build_tree
outputs = builder(**builder_inputs)
File "C:\Users\Positivity\Desktop\GN_Test01.blend\Repeat Grid.py", line 8, in repeat_grid
TypeError: 'NoneType' object is not callable
```