AttributeError: type object '_io.StringIO' has no attribute 'StringIO'

python2導入StringIO模塊，直接：

from StringIO import StringIO

對於python3，StringIO和cStringIO模塊已經沒了，如果要使用的話，需要導入io模塊：

from io import StringIO
dot_data = StringIO()

你也可以導入six模塊來使用StringIO:

from six import StringIO

或

from sklearn.externals.six import StringIO  

例子：對於python2和python3都兼容：

try:
    from StringIO import StringIO
except ImportError:
    from io import StringIO

REF.

[1]http://stackoverflow.com/questions/11914472/stringio-in-python3

[2]https://github.com/pgbovine/OnlinePythonTutor/issues/111

see What’s New In Python 3.0