Update documentation for mandatory flag with BlockingConnection

docs/examples/blocking_publish_mandatory.rst

@@ -1,9 +1,10 @@
 Ensuring message delivery with the mandatory flag
 =================================================
 
-The following example demonstrates how to check if a message is delivered by setting the mandatory flag and checking the return result when using the BlockingConnection::
+The following example demonstrates how to check if a message is delivered by setting the mandatory flag and handling exceptions when using the BlockingConnection::
 
     import pika
+    import pika.exceptions
 
     # Open a connection to RabbitMQ on localhost using all default parameters
     connection = pika.BlockingConnection()
@@ -14,16 +15,17 @@ The following example demonstrates how to check if a message is delivered by set
     # Declare the queue
     channel.queue_declare(queue="test", durable=True, exclusive=False, auto_delete=False)
 
-    # Enabled delivery confirmations
+    # Enabled delivery confirmations. This is REQUIRED.
     channel.confirm_delivery()
 
     # Send a message
-    if channel.basic_publish(exchange='test',
-                             routing_key='test',
-                             body='Hello World!',
-                             properties=pika.BasicProperties(content_type='text/plain',
-                                                             delivery_mode=1),
-                             mandatory=True):
+    try:
+        channel.basic_publish(exchange='test',
+                              routing_key='test',
+                              body='Hello World!',
+                              properties=pika.BasicProperties(content_type='text/plain',
+                                                              delivery_mode=1),
+                              mandatory=True):
         print('Message was published')
-    else:
+    except pika.exceptions.UnroutableError:
         print('Message was returned')