Typo in example dataset class?

[zwep]

Describe the bug

On the page https://docs.aiforoncology.nl/direct/datasets.html there is an example class called 'MyNewDataset'.

There a method is called 'def self.get_dataset_len(self):' which I think should be something like 'def get_dataset_len(self):'

To Reproduce
Go to https://docs.aiforoncology.nl/direct/datasets.html
Check the example dataset implementation

Expected behavior
I expect def get_dataset_len(self): as method definition

Environment
dlup version: Not installed.
direct version: 1.0.5.dev0
How installed: using conda
Python version: 3.9
Operating System:
NAME="Debian GNU/Linux"
VERSION_ID="11"
VERSION="11 (bullseye)"
VERSION_CODENAME=bullseye

Additional context
Add any other context about the problem here.