Adds row aggregation state at the query
        :param raw: list of raw stages or a dict of raw stage
        :return: The current object

def add_raw(self, raw):
        """
        Adds row aggregation state at the query
        :param raw: list of raw stages or a dict of raw stage
        :return: The current object
        """
        if type(raw) == list:
            self._q += raw
        if type(raw) == dict:
            self._q.append(raw)
        return self