def to_python(self, value):
        try:
            value = self.conv.to_python(value)
        except __HOLE__:
            return None
        else:
            if value is not None:
                return self.query.filter_by(id=value).first()
dataset/ETHPy150Open SmartTeleMax/iktomi/iktomi/unstable/forms/convs.py/ModelChoice.to_python