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  "identifier" : "/documentation/Foundation/NSScriptClassDescription/key(withAppleEventCode:)",
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# key(withAppleEventCode:)

Given an Apple event code that identifies a property or element class, returns the key for the corresponding attribute, one-to-one relationship, or one-to-many relationship.

```
func key(withAppleEventCode appleEventCode: FourCharCode) -> String?
```

## Parameters

`appleEventCode`

An Apple event code that identifies a property or element class.

## Return Value

The key that corresponds to the property or element class identified by `appleEventCode` in the receiver or, if none exists, in a class description in the receiver’s superclasses. The four-character Apple event code associated with the attribute or relationship identified by `key` Returns `0` if no such attribute or relationship is found. Returns `nil` if it cannot find any such attribute or relationship.

## See Also

[`-  isReadOnlyKey:`](/documentation/Foundation/NSScriptClassDescription/isReadOnlyKey:)

Returns a Boolean value indicating whether a specified property in the receiver is read-only.


---

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