docs: def _GetBaseURLs(self):
      """Gathers a list of base URLs we will try."""
      result = config.CONFIG["Client.server_urls"]
      if not result:
        # Backwards compatibility - deduce server_urls from Client.control_urls.
        for control_url in config.CONFIG["Client.control_urls"]:
          result.append(posixpath.dirname(control_url) + "/")
  
      # Check the URLs for trailing /. This traps configuration errors.
      for url in result:
        if not url.endswith("/"):
          raise RuntimeError("Bad URL: %s URLs must end with /" % url)
  
      return result