Are dicts supposed to raise comparison errors

[Robin Becker]

messing with bytes I discover that this doesn't warn with python -b

########################
if __name__=='__main__':
     class nbytes(bytes):
         def __eq__(self,other):
             return bytes.__eq__(self,other) if isinstance(other,bytes) else False
         def __hash__(self):
             return bytes.__hash__(self)
     d={'a':1}
     d[nbytes(b'a')] = d['a']
     print(d)
     d={nbytes(b'a'):1}
     d['a'] = d[b'a']
     print(d)
########################


> C:\code\hg-repos\reportlab\tmp>\python37\python -b tb1.py
> {'a': 1, b'a': 1}
> {b'a': 1, 'a': 1}

I expected one of the assignments to warn.
-- 
Robin Becker