class SteelMixin(CalculatorMixin):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

    @classmethod
    def get_by_key(cls, name, spec, material, source, date):
        spec = spec or ''
        material = material or ''
        source = source or ''
        query = cls.query
        query = query.filter(cls.name == name).filter(cls.spec == spec).filter(cls.material == material)
        query = query.filter(cls.source == source).filter(cls.date == date)
        return query.one_or_none()

    def upsert(self):
        result = self.get_by_key(self.name, self.spec, self.material, self.source, self.date)
        if not result:
            session = db.session
            session.add(self)
            session.commit()
        else:
            session = db.session
            self.id = result.id
            session.add(result)
            session.commit()