[BUG] DataFrameGroupBy object has no attribute cumprod

[MarcoGorelli]

Describe the bug
DataFrameGroupBy object has no attribute cumprod

Steps/Code to reproduce bug

df = cudf.DataFrame({'a': [1,1,2], 'b': [4,5,6]})
df.groupby('a')[['b']].cumprod()

---------------------------------------------------------------------------

KeyError                                  Traceback (most recent call last)

[/usr/local/lib/python3.10/dist-packages/cudf/utils/utils.py](https://localhost:8080/#) in __getattr__(self, key)
    227         try:
--> 228             return self[key]
    229         except KeyError:

8 frames

KeyError: 'cumprod'


During handling of the above exception, another exception occurred:

AttributeError                            Traceback (most recent call last)

[/usr/local/lib/python3.10/dist-packages/cudf/utils/utils.py](https://localhost:8080/#) in __getattr__(self, key)
    228             return self[key]
    229         except KeyError:
--> 230             raise AttributeError(
    231                 f"{type(self).__name__} object has no attribute {key}"
    232             )

AttributeError: DataFrameGroupBy object has no attribute cumprod

Expected behavior
same as pandas

 	b
0 	4
1 	20
2 	6

spotted in Narwhals

Environment overview (please complete the following information)

• Environment location: [Bare-metal, Docker, Cloud(specify cloud provider)]
• Method of cuDF install: [conda, Docker, or from source]
  • If method of install is [Docker], provide docker pull & docker run commands used

Environment details
Please run and paste the output of the cudf/print_env.sh script here, to gather any other relevant environment details

google colab, 24.10.01

Additional context
Add any other context about the problem here.