> Reading PEP 0249 I can see Gerhard is correct, this patch would violate the PEP.
Me too.

> I think that the PEP is slightly flawed in that users are encouraged to raise exceptions
> called "Warning".  IMHO a Warning is never an exceptional condition and should be notified
> by the warnings framework.
That’s probably a bad word choice in the PEP.

> This obviously confused the authors of MySQLdb, who do indeed warn() their Warning classes
> rather than raise() them, and it is very useful to be able to filter them.
> To obey the letter of the PEP the authors of the MySQLdb interface multiply inherit their
> Warning class from exceptions.StandardError and exceptions.Warning.
I think they are mistaken, given that the DB API warnings are actually errors.