docs: def update_handler(args):
      """usage: {program} update [<path>]
  
      Update out of date anchors in the current repository.
      """
      repo = _open_repo(args)
  
      for anchor_id, anchor in repo.items():
          try:
              anchor = update(anchor)
          except AlignmentError as e:
              print('Unable to update anchor {}. Reason: {}'.format(
                  anchor_id, e))
          else:
              repo[anchor_id] = anchor