Hello everyone. I'm adding a function to a spreadsheet but it returns "[object Promise]" instead of result. I don't know how to fix it, please help me.

Code Js:

const CAL_AREA = {
    description: _t("Calculate duct area from given dimensions"),
    args: [
        arg("internal_code (string)", _t("The internal code of duct type.")),
        arg("length (number)", _t("Length in mm")),
        arg("width (number)", _t("Width in mm")),
        arg("height (number)", _t("Height in mm")),
        arg("diameter (number)", _t("Diameter in mm")),
        arg("radius (number)", _t("Radius in mm")),
    ],
    category: "Odoo",
    compute: async function (internal_code, length, width, height, diameter, radius) {
        try {
            const result = await this.env.services.rpc("/web/dataset/call_kw", {
                model: "spreadsheet.mixin",
                method: "cal_area",
                args: [[]],
                kwargs: {
                    internal_code,
                    length,
                    width,
                    height,
                    diameter,
                    radius,
                },
            });
            console.log("result: ", result)
            return result;
        } catch (error) {
            console.error("Error in CAL_AREA:", error);
            return 0;
        }
    },
    returns: ["NUMBER"],
};

Code Python: 

def _get_product_duct_type(self, internal_code):
    product = self.env['product.product'].search([('internal_code', '=', internal_code)], limit=1)
    if product:
        return product.duct_type
    return False

def cal_area(self, internal_code, length, width, height, diameter, radius):
    duct_type = self._get_product_duct_type(internal_code)
    area = 0.0
    if duct_type in ['standard_square', 'cone_fitting', 'square_baffle_fitting', 'z_shaped_duct']:
        area = (length + width) * 2 * height / 1000
    elif duct_type == 'round_baffle_fitting':
        area = (diameter * 3.14 * height) / 1000
    elif duct_type == 'square_damper':
        area = ((length + width) * 2 * (radius + length / 2) * 3.14 / 2) / 1000000
    elif duct_type == 'round_damper':
        area = ((diameter * 3.14) * (radius + length / 2) * 3.14 / 2) / 1000000
    return area