refactore double negotiation
@@ -182,7 +182,7 @@ class RcodeZeroDNSDriver(DNSDriver):
value=e.message)
raise e
- if not (extra is None or extra.get('ttl', None) is None):
+ if extra is not None and extra.get('ttl', None) is not None:
ttl = extra['ttl']
else:
ttl = None
