How to use the pfio.read_output function in pfio

while True:
        # get the packet
        packet, sender = sock.recvfrom(BUFFER_SIZE)
        if verbose:
            print "Recieved packet from", sender
        # make it something sensible
        packet = PfionPacket().from_network(packet)

        if packet.command == WRITE_OUT_CMD:
            pfio.write_output(packet.bit_pattern)
            p = PfionPacket(WRITE_OUT_ACK)
            sock.sendto(p.for_network(), sender)

        elif packet.command == READ_OUT_CMD:
            output_bitp = pfio.read_output()
            p = PfionPacket(READ_OUT_ACK)
            p.bit_pattern = output_bitp
            sock.sendto(p.for_network(), sender)

        elif packet.command == READ_IN_CMD:
            input_bitp = pfio.read_input()
            p = PfionPacket(READ_IN_ACK)
            p.bit_pattern = input_bitp
            sock.sendto(p.for_network(), sender)

        elif packet.command == DIGITAL_WRITE_CMD:
            pfio.digital_write(packet.pin_number, packet.pin_value)
            p = PfionPacket(DIGITAL_WRITE_ACK)
            sock.sendto(p.for_network(), sender)

        elif packet.command ==  DIGITAL_READ_CMD:

def read_output():
    """Returns the values of the output pins"""
    global rpi_emulator
    data = __read_pins(rpi_emulator.emu_screen.output_pins)

    global pfio_connect
    if pfio_connect:
        data |= pfio.read_output()

    return data