code: private Result sessionNotFound(String sessionId, String targetPath) {
          if (sessionLoader != null && sessionLoader.apply(sessionId)) {
              if (targetPath != null) {
                  return temporaryRedirect("./" + targetPath);
              } else {
                  return ok();
              }
  
          } else {
              return notFound("Unknown session ID: " + sessionId);
          }
      }
docs: Load StatsStorage via provider, or return "not found"
  @param sessionId session ID to look fo with provider
  @param targetPath one of overview / model / system, or null
  @return temporaryRedirect, ok, or notFound