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: knowledge_base_visibility_class_helper.rb
    path of file: ./repos/zammad/app/helpers
    
    the code of the file until where you have to start completion: # Copyright (C) 2012-2024 Zammad Fou
    
  def visibility_class_name(object)
    return if !can_preview?

    suffix = case object
             when CanBePublished
               visiblity_class_suffix_can_be_published(object)
             when KnowledgeBase::Category
               visiblity_class_suffix_category(object)
             end