We dropped dep on dev-python/sphinx_rtd_theme because the latest dev-python/sphinx already has a dep on it. But for older sphinx versions this will mean that sphinx_rtd_theme maybe won't be installed and installation of dev-python/elasticsearch-py-1.8.0 will fail. We need to re-add the dep on dev-python/sphinx_rtd_theme.
Created attachment 416334 [details, diff] fixed_dep.patch
As per IRC with idella4, we will require a newer sphinx which has a dep on rtd_theme.
Created attachment 416340 [details, diff] fixed_dep.patch
commit 214f2e8872f06a53019855075cbbd580de654d29 Author: Ian Delaney <idella4@gentoo.org> Date: Mon Nov 9 17:49:34 2015 +0800 dev-python/elasticsearch-py: set border version on dep sphinx patch by proxy maintainer in gentoo bug Gentoo bug: #565182