dfg_3dviewer_drupal_module/drush.services.yml

services:
  dfg_3dviewer.commands:
    class: Drupal\dfg_3dviewer\Drush\Commands\Dfg3dViewerCommands
    arguments:
      - '@dfg_3dviewer.config_applier'
    tags:
      - { name: drush.command }