def METHOD_NAME(self, checkResults=False):
    # initialize tank
    tank = Storage_tank_PCM(size_Wh=self.size_storage_Wh,
                            database_model_parameters=self.storage_properties,
                            T_ambient_K=self.T_ambient_K,
                            type_storage=self.type_storage)
    Capex_a_storage_USD, Opex_fixed_storage_USD, Capex_total_USD = tank.costs_storage()
    # calculate results to assert
    results = [tank.V_tank_m3, Capex_a_storage_USD, Opex_fixed_storage_USD, Capex_total_USD]
    # Just for the result comparison - check assertion
    if checkResults:
        np.testing.assert_allclose(results, self.expected_results_costs)
    return results