6599: Fix python3 error

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21945 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
missing import

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21948 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
add TOC entry, for book report

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21949 4ae1f11a-8b86-4847-b8af-ab372f36d1fd