def choice(self, queues, connection):
if not queues:<EOL><INDENT>return None<EOL><DEDENT>return random.choice(list(queues.keys()))<EOL>
Chooses a random queue for messages to specified connection.

@param queues: A C{dict} mapping queue name to queues (sets of frames) to which 
                specified connection is subscribed.
@type queues:  C{dict} of C{str} to C{set} of L{stompclient.frame.Frame}

@param connection: The connection that is going to be delivered the frame(s).
@type connection: L{coilmq.server.StompConnection}

@return: A random queue destination or None if list is empty.
@rtype: C{str}