Faust. How to create a compacting topic

Question

I want to create a topic that is automatically compacted by kafka, using faust stream. I use code like:

import asyncio
import random
import faust

app = faust.App(
    'mysample',
    broker=<...>,
    value_serializer='raw',
    key_serializer='raw',
    topic_replication_factor=3,
)

topic = app.topic('mytest5', partitions=1, compacting=True, acks=False)

count = 1
@app.timer(2.0, on_leader=True)
async def publish_greetings():
    global count
    print('PUBLISHING ON LEADER!')
    await topic.send(key=str(count), value=str(random.random()))
    count += 1

@app.agent(topic)
async def say(greetings):
    async for k, v in greetings.items():
        print(f'{k}, {v}')

I've tried also options internal, retention, deleting with topic creation and every time I changed the topic name, so the new topic should have been created. But I don't see the kafka actually compacts the topic. Every time I read the topic I see the full event history.

How to create a compacting topic with faust?