未调用CreateView中的Django form_valid（）和form_invalid（）

I am currently using django's CreateView to post data to the database. Unfortunately, the method where I would like to save and perform custom logic, form_valid() is never called. I read on another stack overflow response that form_invalid() might uncover the problem, but I can't get that method to call either. The only method that seems to call is get(), which I overrode and put a print statement in. What am I doing wrong? I am currently using django's CreateView to pos