Returns a response signature and query string generated from the
        server response. 'h' aka signature argument is stripped from the
        returned query string.

def parse_parameters_from_response(self, response):
        """
        Returns a response signature and query string generated from the
        server response. 'h' aka signature argument is stripped from the
        returned query string.
        """
        lines = response.splitlines()
        pairs = [line.strip().split('=', 1) for line in lines if '=' in line]
        pairs = sorted(pairs)
        signature = ([unquote(v) for k, v in pairs if k == 'h'] or [None])[0]
        # already quoted
        query_string = '&' . join([k + '=' + v for k, v in pairs if k != 'h'])

        return (signature, query_string)