Using Circuits in Parallel

Question

Is there some easy method to use circuits in parallel in TOR using the STEM API. I wanted to use Website A for Circuit A and Website B for Circuit B. The problem is using threading the event listener is global hence both threads attach streams for both websites on each circuit.

This (attached below) is the function I'm calling in each thread:

def scan(controller, path, websites, numReadings):
    circuit_id = controller.new_circuit(path, await_build = True)

    def attach_stream(stream):
        if stream.status == 'NEW':
            try:
                controller.attach_stream(stream.id, circuit_id)
            except Exception as E:
                print "Scan: " + str(E)
                return 1000


    controller.add_event_listener(attach_stream, stem.control.EventType.STREAM)

    try:
        controller.set_conf('__LeaveStreamsUnattached', '1')  # leave stream management to us
        getPage(controller, websites, numReadings, path)
    finally:
        controller.remove_event_listener(attach_stream)
        controller.reset_conf('__LeaveStreamsUnattached')
        controller.close_circuit(circuit_id)