---
id: 5d792534408c5be896b0a46e
title: Step 37
challengeType: 0
dashedName: step-37
---
# --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`.
# --hints--
See description above for instructions.
```js
assert(
code
.replace(/\s/g, '')
.includes(
'returnstr2.replace(regex,(match,fn,args)=>spreadsheetFunctions.hasOwnProperty(fn.toLowerCase()))'
)
);
```
# --seed--
## --before-user-code--
```html
Spreadsheet
```
## --after-user-code--
```html
```
## --seed-contents--
```html
```
# --solutions--
```html
```