The maximum line length can be specified explicitly via *maxlinelen*. For
splitting the first line to a shorter value (to account for the field header
which isn't included in *s*, e.g. :mailheader:`Subject`) pass in the name of the
- field in *header_name*. The default *maxlinelen* is 76, and the default value
+ field in *header_name*. The default *maxlinelen* is 78, and the default value
for *header_name* is ``None``, meaning it is not taken into account for the
first line of a long, split header.