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.

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))