They were all missing the 'self.' prefix when accessing the 'obj'
instance variable, causing the following exception when attempting to
call len() on (for example) a ReplyInfo_RRSet:
File "/usr/lib/python3.7/site-packages/unboundmodule.py", line 377, in __len__
def __len__(self): return obj.rrset_count
NameError: name 'obj' is not defined