hook(type => "preprocess", id => "googlecalendar",
call => \&preprocess);
hook(type => "format", id => "googlecalendar",
call => \&format);
hook(type => "preprocess", id => "googlecalendar",
call => \&preprocess);
hook(type => "format", id => "googlecalendar",
call => \&format);