code: func (r *Router) AddRoute(rule string, priority int, handler http.Handler) error {
  	parse, err := r.parser.Parse(rule)
  	if err != nil {
  		return fmt.Errorf("error while parsing rule %s: %v", rule, err)
  	}
  
  	buildTree, ok := parse.(treeBuilder)
  	if !ok {
  		return fmt.Errorf("error while parsing rule %s", rule)
  	}
  
  	if priority == 0 {
  		priority = len(rule)
  	}
  
  	route := r.NewRoute().Handler(handler).Priority(priority)
  	return addRuleOnRoute(route, buildTree())
  }
docs: // AddRoute add a new route to the router.