KIP-464 supports creating topics with default partitions and replication factor, but the current interface still asks for num_parititions.

It will be better to let it also be optional, for less confusing.

https://docs.confluent.io/platform/current/clients/confluent-kafka-python/html/index.html#confluent_kafka.admin.NewTopic.NewTopic
https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=113708722