If a AWS Lambda function has event sources from multiple Kinesis streams, will the batch of incoming records be from a single Kinesis stream or a mix?

The title might be a bit confusing. I'll try my best to make it clearer.

Suppose I have a AWS Lambda function that has two different Kinesis streams A and B as input event sources.

So, for the below, since a KinesisEvent instance contains a batch of records, will the batch contain records from a single stream, or essentially it contain records from both streams A and B?

public class ProcessKinesisEvents {
    public void recordHandler(KinesisEvent event, Context context) {
        ...
    }
}