How to use the @pixi/constants.ALPHA_MODES.UNPACK function in @pixi/constants

/**
         * The target type
         *
         * @member {PIXI.TARGETS}
         * @default PIXI.TARGETS.TEXTURE_2D
         */
        this.target = target || TARGETS.TEXTURE_2D;

        /**
         * How to treat premultiplied alpha, see {@link PIXI.ALPHA_MODES}.
         *
         * @member {PIXI.ALPHA_MODES}
         * @default PIXI.ALPHA_MODES.UNPACK
         */
        this.alphaMode = alphaMode !== undefined ? alphaMode : ALPHA_MODES.UNPACK;

        if (options.premultiplyAlpha !== undefined)
        {
            // triggers deprecation
            this.premultiplyAlpha = options.premultiplyAlpha;
        }

        /**
         * Global unique identifier for this BaseTexture
         *
         * @member {string}
         * @protected
         */
        this.uid = uid();

        /**

upload(renderer, baseTexture, glTexture)
    {
        const gl = renderer.gl;

        gl.pixelStorei(gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL, baseTexture.alphaMode === ALPHA_MODES.UNPACK);

        if (glTexture.width === baseTexture.width && glTexture.height === baseTexture.height)
        {
            gl.texSubImage2D(
                baseTexture.target,
                0,
                0,
                0,
                baseTexture.width,
                baseTexture.height,
                baseTexture.format,
                baseTexture.type,
                this.data
            );
        }
        else

upload(renderer, baseTexture, glTexture, source)
    {
        const gl = renderer.gl;
        const width = baseTexture.realWidth;
        const height = baseTexture.realHeight;

        source = source || this.source;

        gl.pixelStorei(gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL, baseTexture.alphaMode === ALPHA_MODES.UNPACK);

        if (!this.noSubImage
            && baseTexture.target === gl.TEXTURE_2D
            && glTexture.width === width
            && glTexture.height === height)
        {
            gl.texSubImage2D(gl.TEXTURE_2D, 0, 0, 0, baseTexture.format, baseTexture.type, source);
        }
        else
        {
            glTexture.width = width;
            glTexture.height = height;

            gl.texImage2D(baseTexture.target, 0, baseTexture.format, baseTexture.format, baseTexture.type, source);
        }

process()
    {
        if (this._process !== null)
        {
            return this._process;
        }
        if (this.bitmap !== null || !window.createImageBitmap)
        {
            return Promise.resolve(this);
        }

        this._process = window.createImageBitmap(this.source,
            0, 0, this.source.width, this.source.height,
            {
                premultiplyAlpha: this.premultiplyAlpha === ALPHA_MODES.UNPACK ? 'premultiply' : 'none',
            })
            .then((bitmap) =>
            {
                if (this.destroyed)
                {
                    return Promise.reject();
                }
                this.bitmap = bitmap;
                this.update();
                this._process = null;

                return Promise.resolve(this);
            });

        return this._process;
    }

upload(renderer, baseTexture, glTexture)
    {
        const gl = renderer.gl;

        gl.pixelStorei(gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL, baseTexture.alphaMode === ALPHA_MODES.UNPACK);

        if (glTexture.width === baseTexture.width && glTexture.height === baseTexture.height)
        {
            gl.texSubImage2D(
                baseTexture.target,
                0,
                0,
                0,
                baseTexture.width,
                baseTexture.height,
                baseTexture.format,
                baseTexture.type,
                this.data
            );
        }
        else