Error setting up Ubuntu Scope dev on 14.04

$ sudo apt-get install unity-scope-tool golang git bzr python3-scope-harness mercurial

[sudo] password for steve:

Reading package lists... Done

Building dependency tree      

Reading state information... Done

Package python3-scope-harness is not available, but is referred to by another package.

This may mean that the package is missing, has been obsoleted, or

is only available from another source

 

E: Package 'python3-scope-harness' has no installation candidate