Creating and playing a sine wave sound (Python)

I'm having a problem running this code with Python 3.1. It complains that the argument of fout.write() must be bytes or buffer, not str. Anyone know how to fix this?

Here is the modification of vegaseat's code that will work with both Python27 and Python32:

# create a sound file in AU format playing a sine wave
# of a given frequency, duration and volume
# vegaseat code modified to work with Python27 and Python32

from struct import pack
from math import sin, pi

def au_file(name='test.au', freq=440, dur=1000, vol=0.5):
    """
    creates an AU format sine wave audio file
    of frequency freq (Hz)
    of duration dur (milliseconds)
    and volume vol (max is 1.0)
    """
    fout = open(name, 'wb')
    # header needs size, encoding=2, sampling_rate=8000, channel=1
    fout.write(pack('>4s5L', '.snd'.encode("utf8"), 24, 8*dur, 2, 8000, 1))
    factor = 2 * pi * freq/8000
    # write data
    for seg in range(8 * dur):
        # sine wave calculations
        sin_seg = sin(seg * factor)
        val = pack('b', int(vol * 127 * sin_seg))
        fout.write(val)
    fout.close()
    print("File %s written" % name)


# test the module ...
if __name__ == '__main__':
    au_file(name='sound440.au', freq=440, dur=2000, vol=0.8)

    # if you have Windows, you can test the audio file
    # otherwise comment this code out
    import os
    os.startfile('sound440.au')

Tried to run the program but had an error on line 4

bellow the error

C:\Users\user pc\AppData\Local\Programs\Python\Python35-32\python "C:\Users\user pc\SkyDrive\ISN\son internet test.py"
Process started >>>
File "C:\Users\user pc\SkyDrive\ISN\son internet test.py", line 4
from struct import pack
^
IndentationError: unexpected indent
Process finished. (Exit code 1)

I'm sure it has nothing to do with the code pasted @Zzucker. Just check your use of tabs and spaces and make sure you've aligned everything right. Python is so particular about indentation (It's part of the syntax).