Hi,

I think the bug is also present in the function encode_quopri which should look like this :

def encode_quopri(msg):
    """Encode the message's payload in quoted-printable.

    Also, add an appropriate Content-Transfer-Encoding header.
    """
    orig = msg.get_payload()
    encdata = _qencode(orig)
    data = str(encdata, "ASCII")
    msg.set_payload(data)
    msg['Content-Transfer-Encoding'] = 'quoted-printable'