Sort by domain name?

[js]

> Gentle reminder: is this homework?  And you can expect better responses
> if you show youve bootstrapped yourself on the problem to some extent.

Sure thing.
First I tried to solve this by using a list of domain found at
http://www.neuhaus.com/domaincheck/domain_list.htm

I converted this to a list (in python) and tried like below

look for url that endswith(domain in domains)
if found:
  capture the left side of the domain part(tld) and
  save all url to a dictionary that key is the captured string

to me this seems to work but stuck because this solution seems no good.