$ gcalcli ERROR: Missing module - No module named gflags Installing python-gflags should help (but version 3.0.2 is broken).
I've opened bug 613850 for a version bump to 3.4.0, including a fix for this too.
commit 8e36163534e38a7b6a4880bbbc1da1bb19a2479d Author: Robin H. Johnson <robbat2@gentoo.org> Date: Tue Aug 15 16:30:25 2017 -0700 app-misc/gcalcli: fixup deps, add last major stable release before 4-alpha Package-Manager: Portage-2.3.6, Repoman-2.3.3