code: def read(self, visibility_timeout=None, callback=None):
          
          def _read(rs):
              if callable(callback):
                  callback(rs[0] if len(rs) == 1 else None)
          self.get_messages(1, visibility_timeout, callback=callback)
docs: Read a single message from the queue.
          
          :type visibility_timeout: int
          :param visibility_timeout: The timeout for this message in seconds
  
          :rtype: :class:`boto.sqs.message.Message`
          :return: A single message or None if queue is empty