When using smtplib to send mail, I meet this bug. Maybe the line
              """ enc = b2a_base64(s[i:i +
max_unencoded]).decode("ascii")""" 
should be changed to
               """ enc = b2a_base64((s[i:i +
max_unencoded]).encode()).decode("ascii")

File "/usr/local/lib/python3.0/smtplib.py", line 580, in login
    AUTH_PLAIN + " " + encode_plain(user, password))
  File "/usr/local/lib/python3.0/smtplib.py", line 545, in encode_plain
    return encode_base64("\0%s\0%s" % (user, password))
  File "/usr/local/lib/python3.0/email/base64mime.py", line 97, in
body_encode
    enc = b2a_base64(s[i:i + max_unencoded]).decode("ascii")
TypeError: b2a_base64() argument 1 must be bytes or buffer, not str