Spot the invalid syntax

[MRAB]

On 2018-03-08 23:23, Ian Pilcher wrote:
> (Because I certainly can't.)
> 
>> def _san_dnsname_ips(dnsname, dnsname_is_cname=False):
>>     """
>>     Returns a set of IP addresses, managed by this IPa instance,
>>     that correspond to the DNS name (from the subjectAltName).
>> 
>>     """
>>     fqdn = dnsutil.DNSName(dnsname).make_absolute()
>>     if fqdn.__len__() < 4:
>>         logger.debug("Skipping IPs for %s: hostname too short" % dnsname)
>>         return ()
>>     zone = dnsutil.DNSName(resolver.zone_for_name(fqdn))
>>     name = fqdn.relativize(zone)
>>     try:
>>         result = api.Command['dnsrecord_show'](zone, name)['result']
>>     except errors.NotFound as nf:
>>         logger.debug("Skipping IPs for %s: %s" % (dnsname, nf))
>>         return ()
>>     ips = set()
>>     for ip in itertools.chain(result.get('arecord', ()),
>>                               result.get('aaaarecord', ())):
>>         if _ip_rdns_ok(ip, fqdn):
>>             ips.add(ip)
>>     cnames = result.get('cnamerecord', ())
>>     if cnames:
>>         if dnsname_is_cname:
>>             logger.debug("Skipping IPs for %s: chained CNAME" % dnsname)
>>         else:
>>             for cname in cnames:
>>                 if not cname.endswith('.'):
>>                     cname = u'%s.%s' % (cname, zone)
>>                 ips.update(_san_dnsname_ips(cname, True)
>>     return ips
> 
> 2.7 and 3.6 are both giving me:
> 
>     File "/tmp/test.py", line 32
>       return ips
>            ^
> SyntaxError: invalid syntax
> 
> I've checked for tabs and mismatched parentheses.
> 
> Aargh!
> 
Look closely at the preceding line. Count the parentheses.