Python logging in PySpark

# ./conf/log4j.properties
[...]
# Set everything to be logged to the console
log4j.rootCategory=INFO, console
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.target=System.err
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=%d{ISO8601} - %c{1} - %p - %m%n
[...]

# ./examples/src/main/python/p.py
[...]
    spark = SparkSession\
        .builder\
        .appName("PythonPi")\
        .getOrCreate()

    sc = spark.sparkContext
    log4jLogger = sc._jvm.org.apache.log4j
    log = log4jLogger.LogManager.getLogger(__name__)
    log.warn("Hello World!")
[...]