[question] python jsonschema cant inheritance

# schema
```python3

class BaseTaskOperateMsg(Record):
task_ids = Array(Integer())

class TaskOffline2OnlineMsg(BaseTaskOperateMsg):
pass
```

# producer
```python3
client = pulsar.Client("pulsar://localhost:6650")
producer = client.create_producer(
topic="taskOffline2Online1",
schema=JsonSchema(TaskOffline2OnlineMsg),
)
msg = TaskOffline2OnlineMsg(task_ids=[1, 2])
producer.send(msg)
client.close()
```

# consumer
```python3
client = pulsar.Client("pulsar://localhost:6650")

consumer = client.subscribe("taskOffline2Online1", "sub1", schema=JsonSchema(TaskOffline2OnlineMsg))

while True:
msg = consumer.receive()
try:
print("Received message '{}' id='{}'".format(msg.data(), msg.message_id()))
print(msg.value())
# Acknowledge successful processing of the message
consumer.acknowledge(msg)
except Exception:
# Message failed to be processed
consumer.negative_acknowledge(msg)
break
```

when using TaskOffline2OnlineMsg, i cant get task_ids.

まず、継承された task_ids フィールドを含め、JsonSchema(TaskOffline2OnlineMsg) を使用した producer と consumer の例を再現します。Python のスキーマ実装で TaskOffline2OnlineMsg と BaseTaskOperateMsg がどのように扱われるかを調査し、その後 consumer が task_ids を取得できるかを確認して、結果を文書化するか、必要な修正を特定します。

索引モデルが issue の本文から書いたものです。