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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 sniff_iface(f):
 """Ensure decorated function is called with a value for iface. If no iface provided, inject net iface inferred from unit private address. """

    def iface_sniffer(*args, **kwargs):
        if not kwargs.get('iface', None):
            kwargs['iface'] = get_iface_from_addr(unit_get('private-address'))

        return f(*args, **kwargs)

    return iface_sniffer