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: certificate_renew_job.rb
    path of file: ./repos/kontena/server/app/jobs
    
    the code of the file until where you have to start completion: class CertificateRenewJob
  include Celluloid
  include Logging
  include CurrentLeader
  include WaitHelper
  include DistributedLocks

  RENEW_INTERVAL = 1.hour.to_i

  RENEW_TRESHOLD = 7.days

  def initialize(perform = true)
    async.perform if perform
  end

  def perform

    
  def perform
    # sleep a while first to allow everything to settle down before running this loop
    sleep 5.minutes
    info 'starting to watch certificate renewals'
    loop do
      if leader?
        with_dlock('cert_renewal_job') {
          renew_certificates
        }
      end
      sleep RENEW_INTERVAL
    end
  end