docs: def add(self, url: str, anything: Any) -> None:
          """
          Register a URL pattern into\
          the routes for later matching.
  
          It's possible to attach any kind of\
          object to the pattern for later\
          retrieving. A dict with methods and callbacks,\
          for example. Anything really.
  
          Registration order does not matter.\
          Adding a URL first or last makes no difference.
  
          :param url: URL
          :param anything: Literally anything.
          """
          url = normalize_url(url)
          parts = url.split('/')
          curr_partial_routes = self._routes
          curr_key_parts = []
  
          for part in parts:
              if part.startswith(':*'):
                  curr_key_parts.append(part[2:])
                  part = self._VAR_ANY_NODE
                  self._max_depth = self._max_depth_custom
  
              elif part.startswith(':'):
                  curr_key_parts.append(part[1:])
                  part = self._VAR_NODE
  
              curr_partial_routes = (curr_partial_routes
                                     .setdefault(part, {}))
  
          curr_partial_routes[self._ROUTE_NODE] = _Route(
              key_parts=curr_key_parts,
              anything=anything)
  
          self._max_depth = max(self._max_depth, depth_of(parts))