---
id: 5d792534408c5be896b0a46e
title: Part 037
challengeType: 0
isBeta: true
---
## Description
The `hasOwnProperty` method checks if a key exists in an object. So `spreadsheetFunctions.hasOwnProperty("")` would return `true`, but replacing `""` with anything else would make it return `false`.
Chain `hasOwnProperty` to `spreadsheetFunctions` to check if the `fn.toLowerCase()` key exists in `spreadsheetFunctions`.
## Instructions
## Tests
```yml
tests:
- text: See description above for instructions.
testString: assert(code.replace(/\s/g, "").includes("returnstr2.replace(regex,(match,fn,args)=>spreadsheetFunctions.hasOwnProperty(fn.toLowerCase()))"));
```
## Challenge Seed
```html
```
### Before Test
### After Test
```html
```
## Solution