Get a variable number of messages.

        :type num_messages: int
        :param num_messages: The maximum number of messages to read from the queue.
        
        :type visibility_timeout: int
        :param visibility_timeout: The VisibilityTimeout for the messages read.

        :type attributes: str
        :param attributes: The name of additional attribute to return with response
                           or All if you want all attributes.  The default is to
                           return no additional attributes.  Valid values:
                           All
                           SenderId
                           SentTimestamp
                           ApproximateReceiveCount
                           ApproximateFirstReceiveTimestamp
                           
        :rtype: list
        :return: A list of :class:`boto.sqs.message.Message` objects.

def get_messages(self, num_messages=1, visibility_timeout=None,
                     attributes=None, callback=None):
        """
        Get a variable number of messages.

        :type num_messages: int
        :param num_messages: The maximum number of messages to read from the queue.
        
        :type visibility_timeout: int
        :param visibility_timeout: The VisibilityTimeout for the messages read.

        :type attributes: str
        :param attributes: The name of additional attribute to return with response
                           or All if you want all attributes.  The default is to
                           return no additional attributes.  Valid values:
                           All
                           SenderId
                           SentTimestamp
                           ApproximateReceiveCount
                           ApproximateFirstReceiveTimestamp
                           
        :rtype: list
        :return: A list of :class:`boto.sqs.message.Message` objects.
        """
        return self.connection.receive_message(self, number_messages=num_messages,
                                               visibility_timeout=visibility_timeout,
                                               attributes=attributes, callback=callback)