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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def main():
 """ Sends an API AT command to read the lower-order address bits from an XBee Series 1 and looks for a response """

    try:

        # Open serial port
        ser = serial.Serial('/dev/ttyUSB0', 9600)

        # Create XBee Series 1 object
        xbee = XBee(ser)


        # Send AT packet
        xbee.send('at', frame_id='A', command='DH')

        # Wait for response
        response = xbee.wait_read_frame()
        print response

        # Send AT packet
        xbee.send('at', frame_id='B', command='DL')

        # Wait for response
        response = xbee.wait_read_frame()
        print response

        # Send AT packet
        xbee.send('at', frame_id='C', command='MY')

        # Wait for response
        response = xbee.wait_read_frame()
        print response

        # Send AT packet
        xbee.send('at', frame_id='D', command='CE')

        # Wait for response
        response = xbee.wait_read_frame()
        print response
    except KeyboardInterrupt:
        pass
    finally:
        ser.close()