Install from PPA under Ubuntu 17.04 fails

Following the installation instructions "sudo apt-add-repository ppa:libadjoint/ppa; sudo apt-get update; sudo apt-get install python-libadjoint" fails:

Package python-libadjoint 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 'python-libadjoint' has no installation candidate