Не могу установить aptitude на терминал Ubuntu

Я хочу установить aptitude я наберу

sudo apt-get install aptitude

bash покажи это:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package aptitude 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 'aptitude' has no installation candidate