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: clean_up_user_export_topics.rb
    path of file: ./repos/discourse/app/jobs/onceoff
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module Jobs
  class CleanUpUserExportTopics < ::Jobs::Onceoff
    def execute_onceoff(args)
      translated_keys =
        I18n
          .available_locales
          .map do |l|
            I18n.with_locale(:"#{l}") do
              I18n.t("system_messages.csv_export_succeeded.subject_template")
            end
          end
          .uniq

      slugs = []
      translated_keys.each { |k| slugs << "%-#{Slug.for(k.gsub("[%{export_title}]", ""))}" }
      # "[%{export_title}] 資料匯出已完成" gets converted to "%-topic", do not match that slug.
      slugs = slugs.reject { |s| s == "%-topic" }

      topics = Topic.with_deleted.where(<<~SQL, slugs, UserExport::DESTROY_CREATED_BEFORE)
        slug LIKE ANY(ARRAY[?]) AND
        archetype = 'private_message' AND
        subtype = 'system_message' AND
        posts_count = 1 AND
        created_at < ? AND
        user_id = -1
     
    
    def execute_onceoff(args)
      translated_keys =
        I18n
          .available_locales
          .map do |l|
            I18n.with_locale(:"#{l}") do
              I18n.t("system_messages.csv_export_succeeded.subject_template")
            end
          end
          .uniq

      slugs = []
      translated_keys.each { |k| slugs << "%-#{Slug.for(k.gsub("[%{export_title}]", ""))}" }
      # "[%{export_title}] 資料匯出已完成" gets converted to "%-topic", do not match that slug.
      slugs = slugs.reject { |s| s == "%-topic" }

      topics = Topic.with_deleted.where(<<~SQL, slugs, UserExport::DESTROY_CREATED_BEFORE)
        slug LIKE ANY(ARRAY[?]) AND
        archetype = 'private_message' AND
        subtype = 'system_message' AND
        posts_count = 1 AND
        created_at < ? AND
        user_id = -1
      SQL

      topics.each do |t|
        Topic.transaction do
          t.posts.first.destroy!
          t.destroy!
        end
      end
    end
  end