def notnull(self):
        return ~self.isnull()
This method is used to postprocess the form files. By default, it
dataset/ETHPy150Open pydata/pandas/pandas/core/categorical.py/Categorical.notnull--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/contrib/formtools/wizard/views.py/WizardView.process_step_files