From Python 3.0 changelog; The StringIO and cStringIO modules are gone. Instead, import the io module and use io.StringIO or io.BytesIO for text and data respectively. From the Python 3 email documentation it can be seen that io.StringIO should be used instead:
from io import StringIO from email.generator import Generator fp = StringIO() g = Generator(fp, mangle_from_=True, maxheaderlen=60) g.flatten(msg) text = fp.getvalue()从Python 3.0开始，StringIO和cStringIO模块已经取消。通过import io模块代替，分别使用io.String或io.BytesIO处理文本和数据。从Python 3邮件流文档能看到相关实现StringIO的代码为：
from io import StringIO from email.generator import Generator fp = StringIO() g = Generator(fp, mangle_from_=True, maxheaderlen=60) g.flatten(msg) text = fp.getvalue()转载于:https://www.cnblogs.com/vercont/p/10210182.html
相关资源：python使用cStringIO实现临时内存文件访问的方法