```ruby
class Chargeback
  class RatesCache
    def get(perf)
      @rates ||= {}
      @rates[perf.hash_features_affecting_rate] ||=
        ChargebackRate.get_assigned_for_target(perf.resource,
                                               :tag_list => perf.tag_list_with_prefix,
                                               :parents  => perf.parents_determining_rate)
    end
  end
end
```

Apply a specific default rate to CB for container images
user
```ruby
class Chargeback
  class RatesCache
    def get(perf)
      @rates ||= {}
      @rates[perf.hash_features_affecting_rate] ||=
        ChargebackRate.get_assigned_for_target(perf.resource,
                                               :tag_list => perf.tag_list_with_prefix,
                                               :parents  => perf.parents_determining_rate)

      if perf.resource_type == Container.name && @rates[perf.hash_features_affecting_rate].empty?
        @rates[perf.hash_features_affecting_rate] = [ChargebackRate.find_by(:description => "Default", :rate_type => "Compute")]
      end
      @rates[perf.hash_features_affecting_rate]
    end
  end
end
```
assistant