Ubuntu 17.04 installation issue

[Gana Bata]

Hello
I have just started to use caffe on ubuntu 17.04 version.
But i have a confusion on caffe installation guide below.

http://caffe.berkeleyvision.org/install_apt.html

where it says that It requires a deb-src line in your sources.list.

I have no idea how to do that but i have googled and tried as follows.

Then tried to update as follows and got the following error:

In what form should i paste the source in the source.list?
I am trying to install from source made by lisa caffe  link is as follows:
https://github.com/xiaolonw/lisa-caffe-lstm

I go the same error even if i just run the command below.

sudo apt build-dep caffe-cuda

Any installation guide how to install caffe on ubuntu 17.04 from source?