decode(s, convert_eols=None)
Decode a raw base64 string.
If convert_eols is set to a string value, all canonical email linefeeds, e.g. "\r\n", in the decoded text will be converted to the value of convert_eols. os.linesep is a good choice for convert_eols if you are decoding a text attachment.
This function does not parse a full MIME header value encoded with base64 (like =?iso-8895-1?b?bmloISBuaWgh?=) -- please use the high level email.Header class for that functionality.