>>> import StringIO
>>> s=StringIO.StringIO()
>>> s.write('hello')
>>> s.getvalue()
'hello'
>>> import io
>>> s=io.StringIO()
>>> s.write('hello')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: string argument expected, got 'str'
>>> s.write(u'hello')
5L
>>> s.getvalue()
u'hello'

C:UsersJohn>python26python -c"import sys,StringIO;s=StringIO.StringIO();s.wr
ite('hellon');print repr(s.getvalue()), sys.version"
'hellon' 2.6.6 (r266:84297, Aug 24 2010, 18:46:32) [MSC v.1500 32 bit (Intel)]

C:UsersJohn>python27python -c"import sys,StringIO;s=StringIO.StringIO();s.wr
ite('hellon');print repr(s.getvalue()), sys.version"
'hellon' 2.7.1 (r271:86832, Nov 27 2010, 18:30:46) [MSC v.1500 32 bit (Intel)]