def is_form(self):
        return self.style.startswith("FORM")
This is needed for both slice assignments and for 
dataset/ETHPy150Open dokterbob/satchmo/satchmo/apps/satchmo_ext/upsell/models.py/Upsell.is_form--crossover with--dataset/ETHPy150Open networkdynamics/zenlib/src/zen/util/bitvector.py/BitVector.__setitem__