Scala KafkaUtils.createDirectStream for calculating the average of every key in DStream

Question

I should write the Scala code for calculating the average of values of every key in a DStream. The stream of key-value pairs are generated in this format:

This is a university project and I should complete a given code. The code is: package sparkstreaming

import java.util.HashMap
import org.apache.kafka.clients.consumer.ConsumerConfig
import org.apache.kafka.common.serialization.StringDeserializer
import org.apache.spark.streaming.kafka._
import kafka.serializer.{DefaultDecoder, StringDecoder}
import org.apache.spark.SparkConf
import org.apache.spark.streaming._
import org.apache.spark.streaming.kafka._
import org.apache.spark.storage.StorageLevel
import java.util.{Date, Properties}
import org.apache.kafka.clients.producer.{KafkaProducer, ProducerRecord, ProducerConfig}
import scala.util.Random

object KafkaSpark {
  def main(args: Array[String]) {
    // make a connection to Kafka and read (key, value) pairs from it
    <FILL IN>
    val kafkaConf = <FILL IN>
    val messages = KafkaUtils.createDirectStream.<FILL IN>
    <FILL IN>

    // measure the average value for each key in a stateful manner
    def mappingFunc(key: String, value: Option[Double], state: State[Double]): (String, Double) = {
    <FILL IN>
    }
    val stateDstream = pairs.mapWithState(<FILL IN>)

    ssc.start()
    ssc.awaitTermination()
  }
}

My biggest problem is that I don't know the syntax for KafkaUtils.createDirectStream for Scala. It is available for Java but not Scala which is quite different. The only provided code for it in Scala is:

import org.apache.kafka.clients.consumer.ConsumerRecord
import org.apache.kafka.common.serialization.StringDeserializer
import org.apache.spark.streaming.kafka010._
import org.apache.spark.streaming.kafka010.LocationStrategies.PreferConsistent
import org.apache.spark.streaming.kafka010.ConsumerStrategies.Subscribe

val kafkaParams = Map[String, Object](
  "bootstrap.servers" -> "localhost:9092,anotherhost:9092",
  "key.deserializer" -> classOf[StringDeserializer],
  "value.deserializer" -> classOf[StringDeserializer],
  "group.id" -> "use_a_separate_group_id_for_each_stream",
  "auto.offset.reset" -> "latest",
  "enable.auto.commit" -> (false: java.lang.Boolean)
)

val topics = Array("topicA", "topicB")
val stream = KafkaUtils.createDirectStream[String, String](
  streamingContext,
  PreferConsistent,
  Subscribe[String, String](topics, kafkaParams)
)

stream.map(record => (record.key, record.value))

Which I really can't understand the syntax.