Identify the error in this Kappa architecture streaming code snippet using Kafka and Spark:

Identify the error in this Kappa architecture streaming code snippet using Kafka and Spark:

stream_df = spark.readStream.format('kafka') \
  .option('kafka.bootstrap.servers', 'localhost:9092') \
  .option('subscribe', 'events') \
  .load()

value_df = stream_df.selectExpr('CAST(value AS STRING)')

query = value_df.writeStream.outputMode('complete').format('console').start()

query.awaitTermination()

What is the problem?