The older Linux sound API (OSS) which is now deprecated is well supported from the standard Python library, through the ossaudiodev module. No native ALSA support exists in the standard library (yet).
There are a few other ``ALSA for Python'' projects available, including at least two different projects called pyAlsa. Neither of these seem to be under active development at the time - and neither are very feature complete.
I wrote PyAlsaAudio to fill this gap. My long term goal is to have the module included in the standard Python library, but that is probably a while of yet.
PyAlsaAudio hass full support for sound capture, playback of sound, as well as the ALSA Mixer API.
MIDI support is not available, and since I don't own any MIDI hardware, it's difficult for me to implement it. Volunteers to work on this would be greatly appreciated