Retrieve registered shortlink info

        Arguments:
            shortlink_id_or_url:
                Shortlink id or url, assigned by mCASH

def get_shortlink(self, shortlink_id_or_url):
        """Retrieve registered shortlink info

        Arguments:
            shortlink_id_or_url:
                Shortlink id or url, assigned by mCASH
        """
        if "://" not in shortlink_id_or_url:
            shortlink_id_or_url = self.merchant_api_base_url + '/shortlink/' + shortlink_id_or_url + '/'

        return self.do_req('GET', shortlink_id_or_url).json()