Without this fix, a verifying dkimpy-milter that has no explicit
AuthservID produces the following crashing behavior as it tries to
create the authres header:
Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/Milter/__init__.py", line 772, in <lambda>
milter.set_eom_callback(lambda ctx: ctx.getpriv().eom())
File "…/dkimpy_milter/__init__.py", line 199, in eom
h = fold(str(h))
File "/usr/lib/python2.7/dist-packages/authres/core.py", line 476, in __str__
return ''.join((self.HEADER_FIELD_NAME, ': ', self.header_value()))
File "/usr/lib/python2.7/dist-packages/authres/core.py", line 496, in header_value
return ''.join(strs)
Daniel Kahn Gillmor
bd1d25d83e