A misprint in the "Big data? 🤗 Datasets to the rescue!" chapter of the NLP Course?

There is the following code in the ["The magic of memory mapping"](https://huggingface.co/learn/nlp-course/chapter5/4#the-magic-of-memory-mapping) section:
```
print(f"Number of files in dataset : {pubmed_dataset.dataset_size}")
size_gb = pubmed_dataset.dataset_size / (1024**3)
print(f"Dataset size (cache file) : {size_gb:.2f} GB")
```
It seems there should be `"Number of bytes in dataset"` instead of `"Number of files in dataset"`, since the number of rows is 15 518 009 and dividing `pubmed_dataset.dataset_size` by `1024**3` suggests measuring information rather than the number of files.