Convert binary data to a line(s) of ASCII characters in quoted-printable encoding.The return value is the converted line(s). If the optional argument *quotetabs* is present and true, all tabs and spaces will be encoded.If the optional argument *istext* is present and true, newlines are not encoded but trailing whitespace will be encoded. If the optional argument *header* is present and true, spaces will be encoded as underscores per :rfc:`1522`. If the optional argument *header* is present and false, newline characters will be encoded as well; otherwise linefeed conversion might corrupt the binary data stream.