python2-notify is available in the updates
repo.
# dnf repoquery --info python2-notify
Last metadata expiration check: 0:01:15 ago on Sun 18 Nov 2018 02:50:34 AM UTC.
Name : python2-notify
Version : 0.1.1
Release : 40.fc29
Arch : x86_64
Size : 35 k
Source : notify-python-0.1.1-40.fc29.src.rpm
Repo : updates
Summary : Python bindings for libnotify
URL : http://www.galago-project.org
License : LGPLv2+
Description : Python bindings for libnotify
If you're trying to install guake and it can't resolve python2-notify, I would check and make sure that you didn't somehow accidentally disable the updates
repo.