How do I "namespace" the crontab entries?

The documentation here (for Capistrano3) says to do this at the bottom of deploy.rb.

set :whenever_identifier, ->{ "#{fetch(:application)}_#{fetch(:stage)}" }

I've done this, but I do not understand how to "namespace the crontab entries." Can someone give me an example of how to do modify my schedule.rb to reflect this "namespace?" (I'm trying to get my whenever entries to NOT run in staging.)

Sorry if this is a stupid question, but I've tried about a half dozen things to make this work, but none of them seem to be up to date, and I can't find an example of this approach.

I have this, but it still creates crontab entries in staging with cap staging whenever:update_crontab:

set :output, "#{path}/log/whenever.log"
env "MAILTO", "david.krider@company.com"

namespace :widget_whammer_production do

  every 1.week do
    runner "FeaturizationNotificationJob.perform_now"
  end

end

Additionally, when doing cap production deploy, I get this error:

/var/www/apps/widget_whammer/shared/bundle/ruby/2.5.0/gems/whenever-1.0.0/lib/whenever/job_list.rb:37:in `method_missing': undefined method `namespace'… from config/schedule.rb:25:in `initialize'

So something is different between cap <stage> deploy vs. cap <stage> whenever:<command>.

Start with the Capistrano3 documentation referenced in the issue, then compare its deploy.rb example with config/schedule.rb and the whenever:update_crontab command. Clarify the difference between cap deploy and cap whenever:, and document a working schedule.rb example that explains what “namespace” means and how staging entries should be handled.