def METHOD_NAME(self, model):
    assert model.fs.unit.config.database is model.db
    assert model.fs.unit._tech_type == "photothermal_membrane"
    assert isinstance(model.fs.unit.water_flux, Var)
    assert isinstance(model.fs.unit.membrane_area, Var)
    assert isinstance(model.fs.unit.wat_flux, Constraint)