chain_final.py

class Handler: #Abstract handler
	"""Abstract Handler"""
	def __init__(self, successor):
		self._successor = successor # Define who is the next handler

	def handle(self, request):
			handled = self._handle(request) #If handled, stop here

			#Otherwise, keep going
			if not handled:
				self._successor.handle(request)	

	def _handle(self, request):
		raise NotImplementedError('Must provide implementation in subclass!')

class ConcreteHandler1(Handler): # Inherits from the abstract handler
	"""Concrete handler 1"""
	def _handle(self, request):
		if 0 < request <= 10: # Provide a condition for handling
			print("Request {} handled in handler 1".format(request))
			return True # Indicates that the request has been handled

class DefaultHandler(Handler): # Inherits from the abstract handler
	"""Default handler"""

	def _handle(self, request):
		"""If there is no handler available"""
		#No condition checking since this is a default handler
		print("End of chain, no handler for {}".format(request))
		return True # Indicates that the request has been handled

class Client: # Using handlers
	def __init__(self):
		self.handler = ConcreteHandler1(DefaultHandler(None)) # Create handlers and use them in a sequence you want
		                                                      # Note that the default handler has no successor

	def delegate(self, requests): # Send your requests one at a time for handlers to handle
		for request in requests:
				self.handler.handle(request)

# Create a client
c = Client()

# Create requests
requests = [2, 5, 30]

# Send the requests
c.delegate(requests)