$ sudo apt-get install python3-lxml python-tox python3-pyqt5 python3-pyqt5.qtwebkit python3-sip python3-jinja2 python3-pygments python3-yaml
Reading package lists... Done
Building dependency tree       
Reading state information... Done
python3-lxml is already the newest version.
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 python-tox : Depends: python-virtualenv but it is not going to be installed
E: Unable to correct problems, you have held broken packages.