I'm currently still struggling with Einstein Analytics and Discovery Insights Specialist (https://trailhead.salesforce.com/en/content/learn/superbadges/superbadge_analytics_insights_specialist?trailmix_creator_id=briankessler&trailmix_id=getting-started-with-analytics) Challenge 2:

My SAQL query is now:
 

beattieSubscribers = load "Beattie_Subs";
tenuredSubscribers = filter beattieSubscribers by row(
               Tenure_Length.selection, 
               [0], 
               ["min","max"]
          ).asRange("Tenure");
churnSubscribers = filter tenuredSubscribers by 'Churn' == "Yes";
groupedSubscribers = group tenuredSubscribers by all full, churnSubscribers by all;
churnRate = foreach groupedSubscribers generate (count(churnSubscribers) / count(tenuredSubscribers))*100 as 'churnRate';

However, this results in the following error displayed on the page:
 

Function doesn't have a type check definition:

.
What is wrong here and how can/should I fix this?

Thanks?