[Spambayes] Eliminating duplicates from mbox file

[Tim Peters]

>     Tim> Looks to me like the email pkg (at least the one in Python CVS)
>     Tim> already does the ">From" bit within msg bodies.

[Skip Montanaro]
> I figured it must have.  Must be something other than the .as_string()
> method though.  It clearly doesn't escape "\nFrom " as "\n>From ".

Stick some prints in the code.  In the _handle_text() method, see whether
this block is getting executed (it should be):

        if self._mangle_from_:
            payload = fcre.sub('>From ', payload)

If it isn't, trace it back from there.

> ...
> I guess I was really asking if there's something better than
> .as_string() to call when I want to emit a message.  I don't see anything
> obvious in the online docs though.

I think Barry usully uses str(msg), which is equivalent to

    msg.as_string(unixfrom=True)

Either way, it leads pretty directly to the _mangle_from code quoted above.