On Thu, 25 Jan 2018 15:18:01 +0000, Steven D'Aprano <report@bugs.python.org> wrote:
> On Thu, Jan 25, 2018 at 02:28:17PM +0000, R. David Murray wrote:
> The docstring for send_message does say 
> 
>     If the sender or any of the recipient addresses contain non-ASCII
>     and the server advertises the SMTPUTF8 capability, the policy is
>     cloned with utf8 set to True for the serialization, and SMTPUTF8
>     and BODY=8BITMIME are asserted on the send.

"Asserted" means sent with the SMTP commands.  It could be reworded to
be clearer.

> which I don't really understand, but I thought that perhaps it was a 
> typo for *inserted* on the send, in the sense of inserted into the mail 
> options:
> 
>     mail_options += ['SMTPUTF8', 'BODY=8BITMIME']

Even if that had been true, it would still be a bug to do it to the
mutable argument :)

> So are we agreed this is a bug? What about the default for rcpt_options 
> being a dict?

I didn't look at that, but it probably is.