code: private static function checkRoutes()
      {
          $method = $_SERVER['REQUEST_METHOD'];
  
          $route_pos = array_keys(self::$routes, self::$uri, true);
  
          foreach ($route_pos as $route) {
              $methodRoute = self::$methods[$route];
  
              if ($methodRoute == $method || $methodRoute == 'ANY') {
                  if (! is_object($callback = self::$callbacks[$route])) {
                      self::$response = self::invokeObject($callback);
                  } else {
                      self::$response = call_user_func($callback);
                  }
  
                  if (! self::$halts) {
                      return self::$response;
                  }
  
                  self::$halts--;
              }
          }
  
          return self::$response;
      }
docs: Check if route is defined without regex.
  
  @return callable|false