def METHOD_NAME(self, line):
    """
    Checks if end of command is reached.
    AT+CGSN and AT+CGSN=0 are not finished by OK, so such cmd is finished when it detects serial_number
    :param line: Line from device.
    :return:
    """
    if self.sn_type == 'default':
        return 'imei' in self.current_ret
    return super(GetImei, self).METHOD_NAME(line)