class ActiveStorage::Service::DiskService

def compose(source_keys, destination_key, **)
  File.open(make_path_for(destination_key), "w") do |destination_file|
    source_keys.each do |source_key|
      File.open(path_for(source_key), "rb") do |source_file|
        IO.copy_stream(source_file, destination_file)
      end
    end
  end
end