The first code example at https://docs.python.org/3.5/library/email-examples.html throws an `AttributeError` because `MIMEText`'s constructor expects a `str` object, not a `bytes` one:

>>> # Import smtplib for the actual sending function
... import smtplib
>>> 
>>> # Import the email modules we'll need
... from email.mime.text import MIMEText
>>> 
>>> # Open a plain text file for reading.  For this example, assume that
... # the text file contains only ASCII characters.
... fp = open(textfile, 'rb')
>>> # Create a text/plain message
... msg = MIMEText(fp.read())
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "/usr/lib/python3.4/email/mime/text.py", line 33, in __init__
    _text.encode('us-ascii')
AttributeError: 'bytes' object has no attribute 'encode'

Patch attached.

LGTM.

Looks like the example wasn't updated during the python3 transition.

As long as we are changing it, we might as well make it use the file as a context manager.

I wasn't sure if that was going to be out of scope or not.

Here's an attached patch that fixes the remaining usages of `open` inside `Doc/includes` to always use a context manager.

New changeset 89c6a6c2dd1f by Berker Peksag in branch '3.4':
Issue #23511: Port email-simple.py to Python 3.
https://hg.python.org/cpython/rev/89c6a6c2dd1f

New changeset cb911e1fb3dc by Berker Peksag in branch 'default':
Issue #23511: Port email-simple.py to Python 3.
https://hg.python.org/cpython/rev/cb911e1fb3dc

Thanks for the patch, Baptiste.