so I have a very simple model called Movies. I'm trying to add a class method which returns a tidy list of the ratings assigned to movies in the database. It seems I'd want to call `Movie.uniq.pluck(:rating)`

So I've added the method like so:

```
class Movie < ActiveRecord::Base

    def self.all_ratings
        self.uniq.pluck(:rating)
    end

end

```

but it just doesn't work. When it runs I get: `undefined method`uniq' for #`... I've tried including ActiveRecord::Calculations but that doesn't seem to help either. I also put a breakpoint in after 'def...' to inspect what methods self had and sure enough, uniq wasn't among them...

I'm clearly doing something wrong, but I just don't quite get what it is.

Anyone have any ideas?

```
ó_ò

```