The publisher application publishes messages to an exchange, with no knowledge of how that exchange is bound to queues or which consumers receive the messages. To publish messages using a topic exchange, specify the name of the exchange and the routing key. Routing keys for a topic exchange are typically multi-part, with the components separated by a period. The publisher publishes five messages with each of the four routing keys. Here's the code that publishes the messages for one of these routing keys, usa.news:

final = "That's all, folks!"

# usa.news
for i in range(5):
  message = Content("message " + str(i))
  message["routing_key"] = "usa.news"
  session.message_transfer(destination="amq.topic", content=message)

message = Content(final)
message["routing_key"] = "usa.news"
session.message_transfer(destination="amq.topic", content=message)

# Now we repeat for "usa.weather", "europe.news", "europe.weather"