Classes issues??????

Since it took me quite some time to figure out, and it 'breaks CSS classes' .
(which I also have seen in some add-ons I can not remember)

Classes constructed 'with python' can turn an extra space into a dot, so:

output += '<li class="my-class another class

ends up like
.myclass. .another . class
in html (notice the . after my class)

Which means that things like
will not work

A workaround is to escape the .
like explained here: