cStringIO.StringIO has no write method?

[Laszlo Nagy]

This program:

import sys
import traceback
import cStringIO

a = 1.0
b = 0.0
try:
    c=a/b
except:    
    f = cStringIO.StringIO('')
    ei = sys.exc_info()
    traceback.print_exception(ei[0],ei[1],ei[2],file=f)

raises this exception:

Traceback (most recent call last):
  File "C:/Documents and Settings/gandalf/test.py", line 12, in ?
    traceback.print_exception(ei[0],ei[1],ei[2],file=f)
  File "C:\Python24\Lib\traceback.py", line 124, in print_exception
    _print(file, 'Traceback (most recent call last):')
  File "C:\Python24\Lib\traceback.py", line 13, in _print
    file.write(str+terminator)
AttributeError: 'cStringIO.StringI' object has no attribute 'write'

What is 'cStringIO.StringI' anyway? Shouldn't it be 'cStringIO.StringIO'?

   Laszlo