Music21 Midi Error: type object '_io.StringIO' has no attribute 'StringIO'. How to fix it?

Question

So, I've followed this question in order to get some sound playing with Music21, and here's the code:

from music21 import *
import random

def main():

#  Set up a detuned piano 
#  (where each key has a random 
#  but consistent detuning from 30 cents flat to sharp)
#  and play a Bach Chorale on it in real time.


    keyDetune = []
    for i in range(0, 127):
        keyDetune.append(random.randint(-30, 30))

    b = corpus.parse('bach/bwv66.6')
    for n in b.flat.notes:
        n.microtone = keyDetune[n.midi]
    sp = midi.realtime.StreamPlayer(b)
    sp.play()

    return 0

if __name__ == '__main__':

    main()

And here's the traceback:

Traceback (most recent call last):
  File "main.py", line 49, in <module>
    main()
  File "main.py", line 44, in main
    sp.play()
  File "G:\Development\Python Development\Anaconda3\lib\site-packages\music21\mi
di\realtime.py", line 104, in play
    streamStringIOFile = self.getStringIOFile()
  File "G:\Development\Python Development\Anaconda3\lib\site-packages\music21\mi
di\realtime.py", line 110, in getStringIOFile
    return stringIOModule.StringIO(streamMidiWritten)
AttributeError: type object '_io.StringIO' has no attribute 'StringIO'
Press any key to continue . . .

I'm running Python 3.4 x86 (Anaconda Distribution) on Windows 7 x64. I have no idea on how to fix this (But probably is some obscure Python 2.x to Python 3.x incompatibility issue, as always)

EDIT:

I've edited the import as suggested in the answer, and now I got a TypeError:

What would you recommend me to do as an alternative to "play some audio" with Music21? (Fluidsynth or whatever, anything).

Answer 1

You may be right... I think the error may actually be in Music21, with the way it handles importing StringIO

Python 2 has StringIO.StringIO, whereas

Python 3 has io.StringIO

..but if you look at the import statement in music21\midi\realtime.py

try:
    import cStringIO as stringIOModule
except ImportError:
    try:
        import StringIO as stringIOModule
    except ImportError:
        from io import StringIO as stringIOModule

The last line is importing io.StringIO, and so later on the call to stringIOModule.StringIO() fails because it's actually calling io.StringIO.StringIO.

I would try to edit the import statement to:

    except ImportError:
        import io as stringIOModule

And see if that fixes it.

Answer 2

return stringIOModule.StringIO(streamMidiWritten) AttributeError: type object '_io.StringIO' has no attribute 'StringIO' Press any key to continue . . .

Please @Ericsson, just remove the StringIO from the return value and you are good to go.

It will now be: return stringIOModule(streamMidiWritten)