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: activities_controller.rb
    path of file: ./repos/ekylibre/app/controllers/backend
    
    the code of the file until where you have to start completion: # == License
# Ekylibre - Simp
    
    def add_itk_on_activities
      begin
        activities = Activity.of_campaign(current_campaign)
      rescue
        notify_error(:no_activities_present)
        return redirect_to(params[:redirect] || { action: :index })
      end