While working with the datasets, I had a few ideas:

(1) sorting the functions that fetch the datasets alphabetically in fetch_example_datasets.py (could make it easier to navigate as the file grows)
(2) also sorting them in api.rst (related #653)
(3) moving tests for those fetch functions to tests/unit/datasets

I'd love to hear your thoughts on whether these 3 changes would be useful/welcomed or if they're not really that important/needed :)