There's also a discrepancy between the docs and the signature for create_aggregate():

https://docs.python.org/3.9/library/sqlite3.html#sqlite3.Connection.create_aggregate

create_aggregate(name, num_params, aggregate_class)

The second parameter is named n_arg, here with an underscore.

I'm not sure what's the best fix; fixing the docs or the signatures. If we fix the signatures, we'll at least get a kind of consistency.