Map cache does not detect function changes in another module
```python
# dataset.py
import os
import datasets

if not os.path.exists('/tmp/test.json'):
  with open('/tmp/test.json', 'w') as file:
    file.write('[{"text": "hello"}]')

def transform(example):
  text = example['text']
  # text += ' world'
  return {'text': text}

data = datasets.load_dataset('json', data_files=['/tmp/test.json'], split='train')
data = data.map(transform)
```

```python
# test.py
import dataset
print(next(iter(dataset.data)))
```

Initialize cache
```
python3 test.py
# {'text': 'hello'}
```

Edit dataset.py and uncomment the commented line, run again
```
python3 test.py
# {'text': 'hello'}
# expected: {'text': 'hello world'}
```

Clear cache and run again
```
rm -rf ~/.cache/huggingface/datasets/*
python3 test.py
# {'text': 'hello world'}
```


If instead the two files are combined, then changes to the function are detected correctly. But it's expected when working on any realistic codebase that things will be modularized into separate files.