docs: def pull_all_external(collector, **kwargs):
      """Pull all the external dependencies of all the images"""
      deps = set()
  
      images = collector.configuration["images"]
      for layer in Builder().layered(images):
          for image_name, image in layer:
              for dep in image.commands.external_dependencies:
                  deps.add(dep)
  
      for dep in sorted(deps):
          kwargs["image"] = dep
          pull_arbitrary(collector, **kwargs)