Is this the right way to use unicode in a user defined Exception?

[一首诗]

#------------------------------------------------
class MyError(Exception):
    def __init__(self):
        self.message = u'Some Chinese:中文'

    def __str__(self):
        return self.message.encode('utf8')
#------------------------------------------------

This is an exception that I defined.   I have to pass it to third
party libraries.

As many libraries simply use str(e) to log, if I don't encode it in
__str___, they will fail.

But I am not quite certain if it's the right thing to do.   Shouldn't
every library expect to use unicode everywhere?

Shouldn't they use something like :

log(unicode(e))