You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: releases_subscription_worker.rb
    path of file: ./repos/gitlabhq/app/workers/activity_pub/projects
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module ActivityPub
  module Projects
    class ReleasesSubscriptionWorker
      include ApplicationWorker
      include Gitlab
    
      def perform(subscription_id)
        subscription = ActivityPub::ReleasesSubscription.find_by_id(subscription_id)
        return if subscription.nil?

        unless subscription.project.public?
          subscription.destroy
          return
        end