One question about "New Producer Configs"

[hi]

Dear sir or madam,

    There is one question when I'm using Kafka:
    From the "documentation:New Producer Configs" ,I get that acks=n means the 
number of acknowledgments the producer requires the leader to have received 
before considering a request complete. But why can the producer  send messages 
successfully when I use the  Producer API‍ and  the acks is set to 2 (the 
number of partitions is 3 but there is only one partition‍ can work)? 

Thanks a lot and look forward to hearing from you soon.

Best Regards,

Genlong Wang
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