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# init(keyName:)

Returns a new custom attribute key with the specified name.

```
convenience init?(keyName: String)
```

## Parameters

`keyName`

The name of the custom attribute for use as a key in a [`CSSearchableItemAttributeSet`](/documentation/CoreSpotlight/CSSearchableItemAttributeSet). The key name must be a string that contains only ASCII characters and no punctuation other than the underscore (that is “_”). The prefix `kMD` is reserved.

## Return Value

A new custom attribute key.

## Discussion

To create custom attribute key names, use a reverse DNS format that includes your company name and does not include the period character (”.”). For example, a key name of the form `com_mycompany_myapp_mykeyname` works well.

---

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