general split_dataset functions

[EnricoTrizio]

Description

Create a single split_dataset function to split datasets in sequential and random mode to fix #91
This deprecates the sequential_split function, which becomes a case of the more general split_dataset function.

Questions

• By default, DeprecationWarnings are not shown. Is it better to print a UserWarning for the sequential_split function?

Status

• Ready to go

[codecov]

Codecov Report

Merging #100 (c9f6138) into main (6e378a6) will decrease coverage by 0.03%.
The diff coverage is 73.33%.

Additional details and impacted files

[andrrizzi]

Looks good! The only thing I'd change is to pass stacklevel=2 to warnings.warn() to print the location of the code that calls the function rather than the location where the function is defined.

By default, DeprecationWarnings are not shown. Is it better to print a UserWarning for the sequential_split function?

Yes, I think DeprecationWarning is ignored by default. There are two solutions. I'd recommend using FutureWarning instead, which is supposed to be still to flag deprecation but to users rather than developers, and it should be printed by default (do test this however). Otherwise, temporarily set the filter might work as well. Something like

warnings.simplefilter('always', category=DeprecationWarning)
warnings.warn(...)
warnings.simplefilter('default', category=DeprecationWarning)

[EnricoTrizio]

Happy 100th PR guys 🥇 🎉
This fixes #91