help.py

def initEventBus():
  loggingAddress = config['loggingAddress']

	def handler(msg):
		print(msg)

	EventBus.register_handler(loggingAddress,handler)

# Exception in Python verticle  
# Traceback (most recent call last):
#   File "main.py", line 33, in <module>
#   File "main.py", line 14, in initEventBus
#   File "__pyclasspath__/core/event_bus.py", line 112, in register_handler
# RuntimeError: handler is required