def METHOD_NAME():
    """Calc spectrum under HAPI"""
    clean_after_run = not exists(HAPIdb) and False
    try:
        db_begin(HAPIdb)
        if not molecule in tableList():  # only if data not downloaded already
            fetch(
                molecule,
                mol_id,
                iso,
                wmin - neighbour_lines,
                wmax + neighbour_lines,
            )
            # HAPI doesnt correct for side effects
        # Calculate with HAPI
        nu, coef = absorptionCoefficient_Voigt(
            SourceTables="CO2",
            Environment={
                "T": T,
                "p": p / 1.01325,
            },  # K  # atm
            WavenumberStep=dnu,
            HITRAN_units=False,
            GammaL="gamma_self",
        )
        nu, trans = transmittanceSpectrum(
            nu,
            coef,
            Environment={
                "l": L,
            },
        )  # cm
        s_hapi = Spectrum.from_array(
            nu,
            trans,
            "transmittance_noslit",
            "cm-1",
            "1",
            conditions={"Tgas": T},
            name="HAPI",
        )
    except:
        raise
    finally:
        if clean_after_run:
            shutil.rmtree(HAPIdb)
    return s_hapi