Pull in this per-package branch with a subtree merge [1]:
$ git merge -s ours --no-commit origin/dev-python/execnet
$ git read-tree --prefix=dev-python/dev-python/execnet/ -u origin/dev-python/execnet
$ git commit -v
so folks who aren't using a version of Layman that supports submodules
(currently everybody) can use this modular package.
[1]: https://www.kernel.org/pub/software/scm/git/docs/howto/using-merge-subtree.html