title: How to produce a Tombstone Avro Record in Kafka using Python?
body: <p><strong>my sink properties :</strong></p>
  
  <pre><code>{
    "name": "jdbc-oracle",
    "config": {
      "connector.class": "io.confluent.connect.jdbc.JdbcSinkConnector",
      "tasks.max": "1",
      "topics": "orders",
      "connection.url": "jdbc:oracle:thin:@10.1.2.3:1071/orac",
      "connection.user": "ersin",
      "connection.password": "ersin!",
      "auto.create": "true",
      "delete.enabled": "true",
      "pk.mode": "record_key",
      "pk.fields": "id",
      "insert.mode": "upsert",
      "plugin.path": "/home/ersin/confluent-5.4.1/share/java/",
      "name": "jdbc-oracle"
    },
    "tasks": [
      {
        "connector": "jdbc-oracle",
        "task": 0
      }
    ],
    "type": "sink"
  }
  </code></pre>
  
  <p><strong>my connect-avro-distributed.properties</strong>   :</p>
  
  <pre><code>bootstrap.servers=10.0.0.0:9092
  
  group.id=connect-cluster
  
  key.converter=io.confluent.connect.avro.AvroConverter
  key.converter.schema.registry.url=http://10.0.0.0:8081
  value.converter=io.confluent.connect.avro.AvroConverter
  value.converter.schema.registry.url=http://10.0.0.0:8081
  
  config.storage.topic=connect-configs
  offset.storage.topic=connect-offsets
  status.storage.topic=connect-statuses
  
  config.storage.replication.factor=1
  offset.storage.replication.factor=1
  status.storage.replication.factor=1
  
  internal.key.converter=org.apache.kafka.connect.json.JsonConverter
  internal.value.converter=org.apache.kafka.connect.json.JsonConverter
  internal.key.converter.schemas.enable=false
  internal.value.converter.schemas.enable=false
  </code></pre>
  
  <p><strong>I send data like this:</strong></p>
  
  <pre><code>from kafka import KafkaProducer
  
  producer = KafkaProducer(
      bootstrap_servers=['10.0.0.0:9092'],
  )
  message=producer.send('orders', key=b'{"id":1}', value=None)
  </code></pre>
  
  <p>But it gives error. Serialization error.</p>