def serve_get(self, path, **params):
        """
        Find a GET callback for the given HTTP path, call it and return the
        results.  The callback is called with two arguments, the path used to
        match it, and params which include the BaseHTTPRequestHandler instance.

        The callback must return a tuple:

            (code, content, content_type)

        If multiple registrations match the path, the one with the longest
        matching text will be used.  Matches are always anchored at the start
        of the path.

        None is returned if no registered callback is willing to handle a path.
    """
        if path is None: return None

        matched = self._match_path(path, self.get_registrations)
        if matched is None:
            return None
        else:
            return matched(path, **params)