Parse token and secret from raw token response.

def parse_raw_token(self, raw_token):
        """Parse token and secret from raw token response."""
        if raw_token is None:
            return (None, None, None)
        qs = parse_qs(raw_token)
        token = qs.get('oauth_token', [None])[0]
        token_secret = qs.get('oauth_token_secret', [None])[0]
        return (token, token_secret, None)