Lesson 9: ReferenceError: sepolia is not defined

[kaleababayneh]

Overview:
I have tried the answer to the exact same question asked before unfortunately the solution provided hasn't worked for me. And I kindly ask for your guidance.
When I run yarn hardhat deploy I get the following error when I comment out networkConfig the error disappears but I would not be able to use sepolia in that case.
It has been 3 days and I still couldn't get over this problem and really appreciate your help.
Here is the full code
https://github.com/itu-itis21-gizaw21/freecodecamp-smart-contract/tree/main/hh-fcc/hardhat-fund-me-fcc

An unexpected error occurred:
Error: ERROR processing skip func of /media/kaleab/Until I win/FCC/hh-fcc/hardhat-fund-me-fcc/deploy/00-deploy-mocks.js:
ReferenceError: sepolia is not defined
    at Object.<anonymous> (/media/kaleab/Until I win/FCC/hh-fcc/hardhat-fund-me-fcc/hepler-hardhat-config.js:6:16)
    at Module._compile (node:internal/modules/cjs/loader:1256:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1310:10)
    at Module.load (node:internal/modules/cjs/loader:1119:32)
    at Function.Module._load (node:internal/modules/cjs/loader:960:12)
    at Module.require (node:internal/modules/cjs/loader:1143:19)
    at require (node:internal/modules/cjs/helpers:110:18)
    at Object.<anonymous> (/media/kaleab/Until I win/FCC/hh-fcc/hardhat-fund-me-fcc/deploy/00-deploy-mocks.js:3:57)
    at Module._compile (node:internal/modules/cjs/loader:1256:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1310:10)
    at DeploymentsManager.executeDeployScripts (/media/kaleab/Until I win/FCC/h

helper-hardhat-config.js

const networkConfig = {
    
   11155111 : {
        name : sepolia,
        ethUsdPriceFeed : "0x694AA1769357215DE4FAC081bf1f309aDC325306",
    }, /*
    137: {
        name : polygon,
        ethUsdPriceFeed : "0xF9680D99D6C9589e2a93a78A04A279e509205945",
    },
    31337 : {
        name : hardhat,
        ethUsdPriceFeed : "0xF9680D99D6C9589e2a93a78A04A279e509205945",
    }*/
}

const developmentChains = ["hardhat","localhost"]
const DECIMALS = 8
const INITIAL_ANSWER = 200000000

module.exports = {
    networkConfig,
    developmentChains,
    DECIMALS,
    INITIAL_ANSWER

[alfaqi]

Make it string, name: "sepolia",

[kaleababayneh]

It worked. Thank you very much!!!