old_contents: #!/usr/bin/env python
  import pika
  import uuid
  
  
  class FibonacciRpcClient(object):
  
      def __init__(self):
          self.connection = pika.BlockingConnection(
              pika.ConnectionParameters(host='localhost'))
  
          self.channel = self.connection.channel()
  
          result = self.channel.queue_declare(queue='', exclusive=True)
          self.callback_queue = result.method.queue
  
          self.channel.basic_consume(
              queue=self.callback_queue,
              on_message_callback=self.on_response,
              auto_ack=True)
  
          self.response = None
          self.corr_id = None
  
      def on_response(self, ch, method, props, body):
          if self.corr_id == props.correlation_id:
              self.response = body
  
      def call(self, n):
          self.response = None
          self.corr_id = str(uuid.uuid4())
          self.channel.basic_publish(
              exchange='',
              routing_key='rpc_queue',
              properties=pika.BasicProperties(
                  reply_to=self.callback_queue,
                  correlation_id=self.corr_id,
              ),
              body=str(n))
          while self.response is None:
              self.connection.process_data_events(None)
          return int(self.response)
  
  
  fibonacci_rpc = FibonacciRpcClient()
  
  print(" [x] Requesting fib(30)")
  response = fibonacci_rpc.call(30)
  print(" [.] Got %r" % response)
  
new_contents: #!/usr/bin/env python
  import pika
  import uuid
  
  
  class FibonacciRpcClient(object):
  
      def __init__(self):
          self.connection = pika.BlockingConnection(
              pika.ConnectionParameters(host='localhost'))
  
          self.channel = self.connection.channel()
  
          result = self.channel.queue_declare(queue='', exclusive=True)
          self.callback_queue = result.method.queue
  
          self.channel.basic_consume(
              queue=self.callback_queue,
              on_message_callback=self.on_response,
              auto_ack=True)
  
          self.response = None
          self.corr_id = None
  
      def on_response(self, ch, method, props, body):
          if self.corr_id == props.correlation_id:
              self.response = body
  
      def call(self, n):
          self.response = None
          self.corr_id = str(uuid.uuid4())
          self.channel.basic_publish(
              exchange='',
              routing_key='rpc_queue',
              properties=pika.BasicProperties(
                  reply_to=self.callback_queue,
                  correlation_id=self.corr_id,
              ),
              body=str(n))
          self.connection.process_data_events(time_limit=None)
          return int(self.response)
  
  
  fibonacci_rpc = FibonacciRpcClient()
  
  print(" [x] Requesting fib(30)")
  response = fibonacci_rpc.call(30)
  print(" [.] Got %r" % response)
  
subject: remove `while self.response is None` loop