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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 get_default_net_device():
 """ Find the device where the default route is. """

    with open('/proc/net/route') as fh:
        for line in fh:
            iface, dest, _ = line.split(None, 2)
            if dest == '00000000':
                return iface
    return None