examples-3.x-dev/modules/file_example/file_example.services.yml

services:
  file_example.state_helper:
    class: Drupal\file_example\FileExampleStateHelper
    arguments: ['@state']
  file_example.file_helper:
    class: Drupal\file_example\FileExampleFileHelper
    arguments: ['@stream_wrapper_manager', '@entity_type.manager', '@file_url_generator']
  file_example.session_helper_wrapper:
    class: Drupal\file_example\FileExampleSessionHelperWrapper
    arguments: ['@stream_wrapper_example.session_helper']
  file_example.submit_handler_helper:
    class: Drupal\file_example\FileExampleSubmitHandlerHelper
    arguments: ['@file_example.state_helper', '@file_example.file_helper', '@file_example.session_helper_wrapper', '@messenger', '@file.repository', '@file_system', '@event_dispatcher']