def ack(self, msg):
message_id = msg['<STR_LIT>']['<STR_LIT>']<EOL>subscription = msg['<STR_LIT>']['<STR_LIT>']<EOL>transaction_id = None<EOL>if '<STR_LIT>' in msg['<STR_LIT>']:<EOL><INDENT>transaction_id = msg['<STR_LIT>']['<STR_LIT>']<EOL>
Called when a MESSAGE has been received.

        Override this method to handle received messages.

        This function will generate an acknowledge message
        for the given message and transaction (if present).