docs: def _append_domain(opts):
      '''
      Append a domain to the existing id if it doesn't already exist
      '''
      # Domain already exists
      if opts['id'].endswith(opts['append_domain']):
          return opts['id']
      # Trailing dot should mean an FQDN that is terminated, leave it alone.
      if opts['id'].endswith('.'):
          return opts['id']
      return '{0[id]}.{0[append_domain]}'.format(opts)