How to use the ufo2ft.CFFOptimization function in ufo2ft

        type=lambda s: CFFOptimization(int(s)),
        default=CFFOptimization.SUBROUTINIZE,

def save_otfs(
        self,
        ufos,
        ttf=False,
        is_instance=False,
        interpolatable=False,
        autohint=None,
        subset=None,
        use_production_names=None,
        subroutinize=None,  # deprecated
        optimize_cff=CFFOptimization.NONE,
        cff_round_tolerance=None,
        remove_overlaps=True,
        overlaps_backend=None,
        reverse_direction=True,
        conversion_error=None,
        feature_writers=None,
        interpolate_layout_from=None,
        interpolate_layout_dir=None,
        output_path=None,
        output_dir=None,
        debug_feature_file=None,
        inplace=True,
    ):
        """Build OpenType binaries from UFOs.

        Args:

exclusive with 'output_path' argument.
        """
        assert not (output_path and output_dir), "mutually exclusive args"

        if output_path is not None and len(ufos) > 1:
            raise ValueError("output_path requires a single input")

        if subroutinize is not None:
            import warnings

            warnings.warn(
                "the 'subroutinize' argument is deprecated, use 'optimize_cff'",
                UserWarning,
            )
            if subroutinize:
                optimize_cff = CFFOptimization.SUBROUTINIZE
            else:
                # for b/w compatibility, we still run the charstring specializer
                # even when --no-subroutinize is used. Use the new --optimize-cff
                # option to disable both specilization and subroutinization
                optimize_cff = CFFOptimization.SPECIALIZE

        ext = "ttf" if ttf else "otf"

        if interpolate_layout_from is not None:
            if interpolate_layout_dir is None:
                interpolate_layout_dir = self._output_dir(
                    ext, is_instance=False, interpolatable=interpolatable
                )
            finder = partial(_varLib_finder, directory=interpolate_layout_dir, ext=ext)
            # no need to generate automatic features in ufo2ft, since here we
            # are interpolating precompiled GPOS table with fontTools.varLib.

help="Run ttfautohint. Can provide arguments, quoted",
    )
    contourGroup.add_argument(
        "--cff-round-tolerance",
        type=float,
        default=None,
        metavar="FLOAT",
        help="Restrict rounding of point coordinates in CFF table to only "
        "those floats whose absolute difference from their integral part "
        "is less than or equal to the tolerance. By default, all floats "
        "are rounded to integer (tolerance 0.5); 0 disables rounding.",
    )
    contourGroup.add_argument(
        "--optimize-cff",
        type=lambda s: CFFOptimization(int(s)),
        default=CFFOptimization.SUBROUTINIZE,
        help="0 disables all optimizations; 1 specializes the CFF charstring "
        "operators; 2 (default) also enables subroutinization",
    )
    contourGroup.add_argument(
        "--no-optimize-gvar",
        dest="optimize_gvar",
        action="store_false",
        help="Do not perform IUP optimization on variable font's 'gvar' table. "
        "(only works with 'variable' TrueType-flavored output)",
    )

    layoutGroup = parser.add_argument_group(title="Handling of OpenType Layout")
    layoutGroup.add_argument(
        "--interpolate-binary-layout",
        nargs="?",
        default=False,

raise ValueError("output_path requires a single input")

        if subroutinize is not None:
            import warnings

            warnings.warn(
                "the 'subroutinize' argument is deprecated, use 'optimize_cff'",
                UserWarning,
            )
            if subroutinize:
                optimize_cff = CFFOptimization.SUBROUTINIZE
            else:
                # for b/w compatibility, we still run the charstring specializer
                # even when --no-subroutinize is used. Use the new --optimize-cff
                # option to disable both specilization and subroutinization
                optimize_cff = CFFOptimization.SPECIALIZE

        ext = "ttf" if ttf else "otf"

        if interpolate_layout_from is not None:
            if interpolate_layout_dir is None:
                interpolate_layout_dir = self._output_dir(
                    ext, is_instance=False, interpolatable=interpolatable
                )
            finder = partial(_varLib_finder, directory=interpolate_layout_dir, ext=ext)
            # no need to generate automatic features in ufo2ft, since here we
            # are interpolating precompiled GPOS table with fontTools.varLib.
            # An empty 'featureWriters' list tells ufo2ft to not generate any
            # automatic features.
            # TODO: Add an argument to ufo2ft.compileOTF/compileTTF to
            # completely skip compiling features into OTL tables
            feature_writers = []