python - サブプロセスでの IOError

Question

PythonでSENNAを使用しようとしています。私は次のようになりますIOError：

Traceback (most recent call last):
  File "C:\Python27\senna_test.py", line 18, in <module>
    tagged = StringIO(p.communicate(sentence)[0])
  File "C:\Python27\lib\subprocess.py", line 479, in communicate
    return self._communicate(input)
  File "C:\Python27\lib\subprocess.py", line 718, in _communicate
    self.stdin.write(input)
IOError: [Errno 22] Invalid argument

私のコードは次のとおりです。

import os
import csv
from StringIO import StringIO
import subprocess as sp
from nltk.draw.tree import Tree, TreeWidget
from nltk.draw.util import CanvasFrame

senna_path="C:/Python27/senna/"
sentence = 'My brother has a dog'

# read senna output
p = sp.Popen(['blabla', '-path',  senna_path],
             executable=os.path.join(senna_path, 'senna-win32.exe'),
             stdin=sp.PIPE,
             stdout=sp.PIPE,
             stderr=sp.PIPE)
tagged = StringIO(p.communicate(sentence)[0])
table = csv.reader(tagged, dialect='excel-tab')