Updates recursively the value in the the config from a JSON file.

        :param filename: (str) a filename of the JSON file
        :param encoding: (str) an encoding of the filename
        :param silent: (bool) fails silently if something wrong with json file

        .. versionadded:: 0.3.0

def from_json(self, filename, encoding='utf-8', silent=False):
        """
        Updates recursively the value in the the config from a JSON file.

        :param filename: (str) a filename of the JSON file
        :param encoding: (str) an encoding of the filename
        :param silent: (bool) fails silently if something wrong with json file

        .. versionadded:: 0.3.0
        """
        self.from_file(json.load, filename, encoding, silent)