def get_format_fn(self):
        if self.transform:
            return TransformFactory.get_transform(self.transform).get_transform_function()
        return None
apply function f to its children.
dataset/ETHPy150Open dimagi/commcare-hq/corehq/apps/userreports/reports/specs.py/ReportColumn.get_format_fn--crossover with--dataset/ETHPy150Open uwescience/raco/raco/algebra.py/Operator.apply