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: refresh_group_update_pull_request.rb
    path of file: ./repos/dependabot-core/updater/lib/dependabot/updater/operations
    
    the code of the file until where you have to start completion: # typed: true
# frozen_string_literal: true

require "dependabot/updater/group_update_creation"
require "dependabot/updater/group_update_refreshing"

# This class implements our strategy for refreshing a single Pull Request which
# updates all outdated D
    
        def dependency_change
          return @dependency_change if defined?(@dependency_change)

          if job.source.directories.nil?
            @dependency_change = compile_all_dependency_changes_for(dependency_snapshot.job_group)
          else
            dependency_changes = job.source.directories.map do |directory|
              job.source.directory = directory
              dependency_snapshot.current_directory = directory
              compile_all_dependency_changes_for(dependency_snapshot.job_group)
            end

            # merge the changes together into one
            @dependency_change = dependency_changes.first
            @dependency_change.merge_changes!(dependency_changes[1..-1]) if dependency_changes.count > 1
            @dependency_change
          end