Comment accepter la licence steam lors de l'installation de steam ?

Comme indiqué dans comment installer steam on est censé courir :

sudo apt-get install steam

Pourtant, j'obtiens la sortie d'erreur que j'ai refusé l'accord de licence de Steam :

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  steam:i386
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/874 kB of archives.
After this operation, 2.662 kB of additional disk space will be used.
Preconfiguring packages ...
(Reading database ... 718351 files and directories currently installed.)
Preparing to unpack .../steam_1%3a1.0.0.48-1ubuntu3_i386.deb ...
dpkg: error processing archive /var/cache/apt/archives/steam_1%3a1.0.0.48-1ubuntu3_i386.deb (--unpack):
 subprocess new pre-installation script returned error exit status 30
Installation terminated: Steam License Agreement was DECLINED.
Errors were encountered while processing:
 /var/cache/apt/archives/steam_1%3a1.0.0.48-1ubuntu3_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Comment accepter la licence steam et installer steam via apt-get install steam ? Il n'y a pas eu de popup d'information, pas de sélection à faire. Par défaut, c'est refusé.

Je sais que je peux télécharger le fichier deb pourtant je veux utiliser le référentiel.