Jacek Laskowski's code is not-working

spark_24_foreachbatch.txt

scala> println("This answer actually got some points on SO https://stackoverflow.com/a/53981675/918211")
This answer actually got some points on SO https://stackoverflow.com/a/53981675/918211

scala> println(spark.version)
2.4.0

scala> val sq = spark.readStream.format("rate").load
sq: org.apache.spark.sql.DataFrame = [timestamp: timestamp, value: bigint]

scala> :type sq
org.apache.spark.sql.DataFrame

scala> assert(sq.isStreaming)

scala> :paste
// Entering paste mode (ctrl-D to finish)

import org.apache.spark.sql.DataFrame
sq.writeStream.foreachBatch { case (ds: DataFrame, batchId: Long) =>
  // do whatever you want with your input DataFrame
  // incl. writing to Hive
  // I simply decided to print out the rows to the console
  ds.show
}.start

// Exiting paste mode, now interpreting.

<pastie>:28: warning: non-variable type argument org.apache.spark.sql.Row in type pattern org.apache.spark.sql.Dataset[org.apache.spark.sql.Row] (the underlying of org.apache.spark.sql.DataFrame) is unchecked since it is eliminated by erasure
       sq.writeStream.foreachBatch { case (ds: DataFrame, batchId: Long) =>
                                               ^
<pastie>:28: error: missing parameter type for expanded function
The argument types of an anonymous function must be fully known. (SLS 8.5)
Expected type was: ?
       sq.writeStream.foreachBatch { case (ds: DataFrame, batchId: Long) =>
                                   ^