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: import_articles_worker.rb
    path of file: ./repos/forem/app/workers/feeds
    
    the code of the file until where you have to start completion: module Feeds
  class ImportArticlesWorker
    include Sidekiq::Job

    sidekiq_options queue: :medium_p
    
    def perform(user_ids = [], earlier_than = nil)
      users_scope = User

      if user_ids.present?
        users_scope = users_scope.where(id: user_ids)
        # we assume that forcing a single import should not take into account
        # the last time a feed was fetched at
        earlier_than = nil
      else
        users_scope = users_scope.where(id: Users::Setting.with_feed.select(:user_id))
        earlier_than ||= 4.hours.ago
      end