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: mentioner.rb
    path of file: ./repos/bootcamp/app/models/concerns
    
    the code of the file until where you have to start completion: # frozen_string_lite
    
  def where_mention
    case self
    when Product
      "#{user.login_name}さんの提出物「#{practice[:title]}」"
    when Report
      "#{user.login_name}さんの日報「#{self[:title]}」"
    when Comment
      "#{target_of_comment(commentable.class, commentable)}へのコメント"
    when Answer
      "#{receiver.login_name}さんのQ&A「#{question[:title]}」へのコメント"
    when Question
      practice_title = practice ? practice[:title] : 'プラクティス選択なし'
      "#{user.login_name}さんのQ&A「#{practice_title}」"
    end