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: duplicate_job.rb
    path of file: ./repos/gitlabhq/lib/gitlab/sidekiq_middleware/duplicate_jobs
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require 'digest'
require 'msgpack'

module Gitlab
  module SidekiqMiddleware
    module DuplicateJobs
      # This class defines an identifier of
    
        def update_latest_wal_location!
          return unless job_wal_locations.present?

          argv = []
          job_wal_locations.each do |connection_name, location|
            diff = pg_wal_lsn_diff(connection_name)
            argv += [connection_name, diff ? diff.to_f : '', location]
          end

          with_redis { |r| r.eval(UPDATE_WAL_COOKIE_SCRIPT, keys: [cookie_key], argv: argv) }
        end