Author: (no author) not defined in authors file

I'm still using git as my Subversion client and just today I came over this strange error message:

Author: (no author) not defined in /path/to/repos/authors.txt file

I'm not sure how the author can be missing on any commits in the Subversion repository, but the solution was quite simple. Just add an author called "(no author)" to the authors file like this:

(no author) = No Author <no.author@mail.com>

And then continue as normal with git svn fetch