please refer to the following cmd for how to sending messages to broker.
python3 deepstream_test_4.py -i /opt/nvidia/deepstream/deepstream/samples/streams/sample_720p.h264 -p /opt/nvidia/deepstream/deepstream/lib/libnvds_kafka_proto.so --conn-str="localhost;9092" -t deepstream -s 0 --no-display
if you need to receive message from broker. please port the logics in start_cloud_to_device_messaging of \opt\nvidia\deepstream\deepstream\sources\apps\apps-common\src\deepstream_c2d_msg.c to python code. subscribe_cb is subscribe callback function.