Não é possível instalar a ferramenta de ajuste de unidade no Ubuntu 16.04?

Question

Eu tinha instalado o "Unity Tweak Tool". Mas agora desapareceu.

Quando tentei instalar novamente, mostra a seguinte saída de sudo apt-get install unity-tweak-tool

Reading package lists... Done
Building dependency tree       
Reading state information... Done
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:
 unity-tweak-tool : Depends: unity-webapps-common but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

Screenshot -