我正在尝试用pykafka创建一个简单的客户机。为此，我需要ssl证书。客户端在RHEL7和Python3.6.x下运行，看起来连接正常，但我没有得到任何反馈或数据，只有一个黑屏。如何检查连接或获取错误消息。

# !/usr/bin/scl enable rh-python36 -- python3

from pykafka import KafkaClient, SslConfig

config = SslConfig(cafile='key/root_ca.crt',
                   certfile='key/cert.crt',  
                   keyfile='key/key.key',
                   password='xxxx') 

client = KafkaClient(hosts="xxxxxxx:9093", 
                        ssl_config=config)

print("topics", client.topics) 

topic = client.topics['xxxxxx']

consumer = topic.get_simple_consumer(
                    consumer_group="yyyyy",
                    auto_offset_reset=OffsetType.EARLIEST,
                    reset_offset_on_start=False
                    )

for message in consumer:
    if message is not None:
        print (message.offset, message.value)