[stickperson]

  Grouping of sub-dependency groups (e.g. a testing group).

That seems like an improvement over having multiple requirement files. Then again, I'm perfectly happy with separate dev/testing files.

[davvid]

One use case I don't see covered is grouping by python versions. Sometimes "soft" dependencies are only available/supported/not-broken on certain python versions.

It'd be nice to be able to mark a dependency as being conditional based on some expression, e.g. `$PYTHON_VERSION_MAJOR >= 3`.

[witten]

BTW, you can do that already with requirements.txt. See https://stackoverflow.com/questions/19559247/requirements-tx...

[examancer]

Give it time. Moving to a native python DSL will make extending the dependency system more straightforward. Also, if they continue copying the best of Ruby's bundler they will have a way to specify python version/platform specific dependencies.