def merge_from_initial(self):
        self.data._mutable = True
        filt = lambda v: self.data.keys() not in v
        for field in filter(filt, getattr(self.Meta, 'fields', ())):
            self.data[field] = self.initial.get(field, None)
dataset/ETHPy150Open dgraziotin/dycapo/piston/forms.py/ModelForm.merge_from_initial/swapped operands of `not in`