issue with the Setting up your Linux (Ubuntu) workstation as a development environment lab

[SubieNinja]

im stuck on the 3rd part of step 7 of getting my linux machine set up for cisco devnet labs.

https://developer.cisco.com/learning/modules/dev-setup/dev-ubuntu/step/8

the slide says:

• Add the Docker repository to apt in order to always check for the latest stable version:

   sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
  

so i popped that into my terminal and this is what i get:

ThinkPad-Edge-E535:~$ sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
Malformed input, repository not added.

not sure what the issue is here but i really want to finish setting this up so i can start labbing