code: def clean(ctx, dry_run=False):
      
      # -- VARIATION-POINT 1: Allow user to override in configuration-file
      directories = ctx.clean.directories
      files = ctx.clean.files
  
      # -- VARIATION-POINT 2: Allow user to add more files/dirs to be removed.
      extra_directories = ctx.clean.extra_directories or []
      extra_files = ctx.clean.extra_files or []
      if extra_directories:
          directories.extend(extra_directories)
      if extra_files:
          files.extend(extra_files)
  
      # -- PERFORM CLEANUP:
      execute_cleanup_tasks(ctx, cleanup_tasks, dry_run=dry_run)
      cleanup_dirs(directories, dry_run=dry_run)
      cleanup_files(files, dry_run=dry_run)
docs: Cleanup temporary dirs/files to regain a clean state.