TypeError: Object of type module is not JSON serializable

Question

I use the json.dumps() to pack datas as follow, using complex_signal.tolist() or str(complex_signal) is same result too;

import json

#send to kafka
def Send(complex_signal, frequency, time):
    signal = {  # 
        "time": time,
        "frequency": frequency,
        "complex_signal": complex_signal# this is a ndarray type
    }

    msg = json.dumps(signal)
    producer.produce('topic_test', key=None, value=msg)

console out :raise TypeError(f'Object of type {o.class.name} ' TypeError: Object of type module is not JSON serializable

JSON,I use rtl-sdr to get signal and send it to kafka .