<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def consume(self, callback, bindings, queues):
 """ Start a consumer that lasts across individual connections. Args: callback (callable):
 A callable object that accepts one positional argument, a :class:`Message` or a class object that implements the ``__call__`` method. The class will be instantiated before use. bindings (dict or list of dict):
 Bindings to declare before consuming. This should be the same format as the :ref:`conf-bindings` configuration. queues (dict):
 The queues to declare and consume from. Each key in this dictionary is a queue, and each value is its settings as a dictionary. These settings dictionaries should have the "durable", "auto_delete", "exclusive", and "arguments" keys. Refer to :ref:`conf-queues` for details on their meanings. Returns: defer.Deferred: A deferred that fires with the list of one or more :class:`fedora_messaging.twisted.consumer.Consumer` objects. These can be passed to the :meth:`FedoraMessagingFactoryV2.cancel` API to halt them. Each consumer object has a ``result`` instance variable that is a Deferred that fires or errors when the consumer halts. The Deferred may error back with a BadDeclaration if the user does not have permissions to consume from the queue. """

        expanded_bindings = collections.defaultdict(list)
        for binding in bindings:
            for key in binding["routing_keys"]:
                b = binding.copy()
                del b["routing_keys"]
                b["routing_key"] = key
                expanded_bindings[b["queue"]].append(b)

        expanded_queues = []
        for name, settings in queues.items():
            q = {"queue": name}
            q.update(settings)
            expanded_queues.append(q)

        protocol = yield self.when_connected()

        consumers = []
        for queue in expanded_queues:
            yield protocol.declare_queues([queue])
            b = expanded_bindings.get(queue["queue"], [])
            yield protocol.bind_queues(b)
            consumer = yield protocol.consume(callback, queue["queue"])
            self._consumers[queue["queue"]] = (consumer, queue, b)
            consumers.append(consumer)

        defer.returnValue(consumers)