Although the reference docs don't list the numeric values of logging levels, this happened during reorganising of the docs. The table has moved to the HOWTO:

http://docs.python.org/howto/logging.html#logging-levels

That said, I don't understand the need for special logging levels in the multiprocessing package. From the section following the one linked to above:

"Defining your own levels is possible, but should not be necessary, as the existing levels have been chosen on the basis of practical experience. However, if you are convinced that you need custom levels, great care should be exercised when doing this, and it is possibly *a very bad idea to define custom levels if you are developing a library*. That’s because if multiple library authors all define their own custom levels, there is a chance that the logging output from such multiple libraries used together will be difficult for the using developer to control and/or interpret, because a given numeric value might mean different things for different libraries."