Part of twisted.python.log.LogPublisher View Source
The message should be a native string, i.e. bytes on Python 2 and Unicode on Python 3. For compatibility with both use the native string syntax, for example:
>>> log.msg('Hello, world.')
You MUST avoid passing in Unicode on Python 2, and the form:
>>> log.msg('Hello ', 'world.')
This form only works (sometimes) by accident.