I entered the following command on ubuntu 14.04
sudo apt-get install python3.6-dev libmysqlclient-dev
It gives the following error
The following packages have unmet dependencies:
libmysqlclient-dev : Depends: libmysqlclient18 (= 5.5.59-0ubuntu0.14.04.1) but 10.2.13+maria~trusty is to be installed
W: Duplicate sources.list entry https://repo.skype.com/deb/ stable/main amd64 Packages (/var/lib/apt/lists/repo.skype.com_deb_dists_stable_main_binary-amd64_Packages)
W: You may want to run apt-get update to correct these problems
E: Unable to correct problems, you have held broken packages.
apt-get update
?repo.skype.com
? Also runapt-mark showhold
to see the held packages.