'Create new message of appropriate class.
:type body: message body
:param body: The body of the newly created message (optional).
:rtype: :class:`boto.sqs.message.Message`
:return: A new Message object'

def new_message(self, body='', **kwargs):

    m = self.message_class(self, body, **kwargs)
    m.queue = self
    return m
