Error: invalid BigNumber value (argument="value", value=undefined, code=INVALID_ARGUMENT, version=bignumber/5.7.0)

Error: invalid BigNumber value (argument="value", value=undefined, code=INVALID_ARGUMENT, version=bignumber/5.7.0)

PS E:\Block Chain Projects\FUND_ME_FULLSTACK> yarn hardhat test
yarn run v1.22.15
warning ..\package.json: No license field
$ "E:\Block Chain Projects\FUND_ME_FULLSTACK\node_modules\.bin\hardhat" test


  Funde
    constructor
      ✔ Sets the aggregator address correctly (50ms)
    Fund
      ✔ Fails if u don't send enought ethers (147ms)
      ✔ Update the amount funded data structure (104ms)
      ✔ Funder Upated to fund array (108ms)
    Withdraw
      1) Withdraw Eth From a single Founder

  4 passing (2s)
  1 failing

  1) Funde
       Withdraw
         Withdraw Eth From a single Founder:
     Error: invalid BigNumber value (argument="value", value=undefined, code=INVALID_ARGUMENT, version=bignumber/5.7.0)
      at Logger.makeError (node_modules\@ethersproject\logger\src.ts\index.ts:269:28)
      at Logger.throwError (node_modules\@ethersproject\logger\src.ts\index.ts:281:20)
      at Logger.throwArgumentError (node_modules\@ethersproject\logger\src.ts\index.ts:285:21)
      at Function.BigNumber.from (node_modules\@ethersproject\bignumber\src.ts\bignumber.ts:289:23)    
      at toBN (node_modules\@ethersproject\bignumber\src.ts\bignumber.ts:345:27)
      at BigNumber.mul (node_modules\@ethersproject\bignumber\src.ts\bignumber.ts:90:43)
      at Context.<anonymous> (test\units\FundMe.test.js:58:42)
      at processTicksAndRejections (node:internal/process/task_queues:96:5)
      at runNextTicks (node:internal/process/task_queues:65:3)
      at listOnTimeout (node:internal/timers:528:9)

MY FundMe.test.js The Problem is in Withdraw Describe (ERROR of BIGNUMBER ) unable to find the bug

const {deployments, ethers,getNamedAccounts} = require("hardhat");
const {assert, expect} = require("chai");
describe("Funde",async function () {
    let fundme;
    let deployer;
    let mockV3Aggregator;
    let  sendvalue = ethers.utils.parseEther("1"); //! Ether
    beforeEach(async ()=>
    {
        // DEPLOY THE CONTRACT USING HARDHAT DEPLOY
        deployer = (await getNamedAccounts()).deployer;
        await deployments.fixture("all"); // -> with one line of code deploy all deploy.js files
        // fixture uses tags given in the deploy folders using module.exports\
        //console.log(deployer);
        fundme = await ethers.getContract("FundMe",deployer);
        mockV3Aggregator = await ethers.getContract("MockV3Aggregator",deployer);
    });
    describe("constructor",async function()
    {
        it("Sets the aggregator address correctly",async function()
        {   const response = await fundme.getPriceFeed();
            ////console.log(response);
            //console.log(mockV3Aggregator.address);
            assert.equal(response,mockV3Aggregator.address);

        });
    });
    describe("Fund",async function()
    {
        it("Fails if u don't send enought ethers",async function ()
        {
            await expect(fundme.fund()).to.be.revertedWith("You need to spend more ETH!");
        });
        it("Update the amount funded data structure",async ()=>{
            await fundme.fund({value:sendvalue})
            const response = await fundme.getAddressToAmountFunded(deployer);
            assert.equal(response.toString(),sendvalue.toString());
        });
        it("Funder Upated to fund array",async () =>{
            await fundme.fund({value:sendvalue})
            const response = await fundme.getFunder(0);
            assert.equal(response,deployer);
        });
    });
    describe("Withdraw",async function(){
        beforeEach(async function(){
            await fundme.fund({value:sendvalue});
        })
        it("Withdraw Eth From a single Founder",async function()
        {
            //Arrange
            const initialbalance = await fundme.provider.getBalance(fundme.address);
            const initialdeploybalance = await fundme.provider.getBalance(deployer);
            //ACT
            const withdrawfund = await fundme.withdraw();
            const Transactionreciept = await withdrawfund.wait();
            const {gasUsed,effecttiveGasPrice} = Transactionreciept;
            const totalgasused = gasUsed.mul(effecttiveGasPrice);
            console.log(totalgasused);
            const Endingbalance = await fundme.provider.getBalance(fundme.address);
            const Endingdeployerbalance = await fundme.provider.getBalance(deployer);
            //ASSERT
            assert.equal(Endingbalance,0);
            assert.equal(initialbalance.add(initialdeploybalance)
            .toString(),
            Endingdeployerbalance.add(totalgasused)
            .toString());
        });
    });
});

const totalgasused = gasUsed.mul(effecttiveGasPrice); I think the error is in this line WHY Am I unable to get the totalgasused..I tried JS-DEBUGGER TO but was unable to find the bug