How installing ShotWell from PPA

[kalpana]

hello

I'm using Ubuntu 14.04
To have the last version of Shotwell, I try the procedure proposed here:
http://doc.ubuntu-fr.org/shotwell

sudo add-apt-repository ppa:yorba/ppa
sudo apt-get update
sudo apt-get install shotwell

However, I get an error message during instalation:

Des erreurs ont été rencontrées pendant l'exécution :
/var/cache/apt/archives/shotwell_0.20.1-1~trusty1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

and I remain in version 0.18.0

How do I install 0.20.1 from a ppa?

Thank you