def insert(self, index, value):
    self.__field.validate_element(value)
    return list.insert(self, index, value)


# TODO(rafek): Prevent additional field subclasses.
Initialize BaseCaseVersionForm, including StepFormSet.
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/protorpc/protorpc/messages.py/FieldList.insert--crossover with--dataset/ETHPy150Open mozilla/moztrap/moztrap/view/manage/cases/forms.py/BaseCaseVersionForm.__init__