compose

# File activestorage/lib/active_storage/service/disk_service.rb, line 105
    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