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: 20140618001820_dont_auto_muto_topics.rb
    path of file: ./repos/discourse/db/migrate
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

class DontAutoMutoTopics < ActiveRe
    
  def change
    # muting all new topics was a mistake, revert it
    execute "DELETE FROM topic_users WHERE notification_level = 0 and notifications_reason_id =7 AND first_visited_at IS NULL"

    execute "UPDATE topic_users SET notification_level = 1,
                                    notifications_reason_id = NULL
            WHERE notification_level = 0 AND notifications_reason_id =7"
  end