def validate(self, data):
        """
        We need to set some timestamps according to the accounting packet type
        * update_time: set everytime a Interim-Update / Stop packet is received
        * stop_time: set everytime a Stop packet is received
        * session_time: calculated if not present in the accounting packet
        :param data: accounting packet
        :return: Dict accounting packet
        """
        time = timezone.now()
        status_type = data.pop('status_type')
        if status_type == 'Interim-Update':
            data['update_time'] = time
        if status_type == 'Stop':
            data['update_time'] = time
            data['stop_time'] = time
        return data
We need to set some timestamps according to the accounting packet type
        * update_time: set everytime a Interim-Update / Stop packet is received
        * stop_time: set everytime a Stop packet is received
        * session_time: calculated if not present in the accounting packet
        :param data: accounting packet
        :return: Dict accounting packet