more explicit example

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/pks@147 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
cosmetics

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/pks@148 edb9625f-4e0d-4859-8d74-9fd3b1da38cb