code: def set_topic_attributes(self, topic, attr_name, attr_value):
          
          params = {'ContentType' : 'JSON',
                    'TopicArn' : topic,
                    'AttributeName' : attr_name,
                    'AttributeValue' : attr_value}
          response = self.make_request('SetTopicAttributes', params, '/', 'GET')
          body = response.read()
          if response.status == 200:
              return json.loads(body)
          else:
              boto.log.error('%s %s' % (response.status, response.reason))
              boto.log.error('%s' % body)
              raise self.ResponseError(response.status, response.reason, body)
docs: Get attributes of a Topic
  
          :type topic: string
          :param topic: The ARN of the topic.
  
          :type attr_name: string
          :param attr_name: The name of the attribute you want to set.
                            Only a subset of the topic's attributes are mutable.
                            Valid values: Policy | DisplayName
  
          :type attr_value: string
          :param attr_value: The new value for the attribute.