import pymod
from math import sin, pi

samplerate = 44100
channels = 2

x = pymod._ysynth_init(samplerate, channels)

samples_processed = 0

def sine_wave(channels):
    """
    Send simple 440Hz to your speakers
    """

    global samples_processed

    if not samples_processed:
        print "First time callback occurred"
        print "Array shape is: %s" % str(channels.shape)

    for i in xrange(channels.shape[0]):
        channels[i][0] = channels[i][1]= sin(440.0 * (i + samples_processed) /
            samplerate * (pi * 2.0)) * 20000

    samples_processed += channels.shape[0]

    return

pymod._ysynth_set_callback(x, sine_wave)