Unfortunately Google has removed this feature, we are looking at ways to implement this again however it is currently not possible.
ah, so that's why you have the import by dates... I was unable to import my whole classroom because it has more than 150 assignments. That topic feature was perfect since I'm elementary and I could import each topic and have a grade. I'm going to rethink next year's build on classroom so I can get around this.
@Deborah Manis Good news, import by topics is back! Please make sure you have v2.35