[pygame] loopwave.py equivalent?

[Will Woods <will.woods2@xxxxxxxxx>]

I want to be able to continuously modify a sound buffer from a
callback, exactly as shown in the pygame 0.09 example loopwave.py

http://hg.pygame.org/pygame/src/d1cbb8c9d94b/test/loopwave.py

This uses direct access to SDL which seems to have disappeared in more
recent versions of pygame. I need to be able to  continuously vary the
frequency modulation of a tone in response to user input.

Will