dump DictTree data to json files.

def dump(self, path):
        """
        dump DictTree data to json files.
        """
        try:
            with open(path, "wb") as f:
                f.write(self.__str__().encode("utf-8"))
        except:
            pass

        with open(path, "wb") as f:
            pickle.dump(self.__data__, f)