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# kSecTransformPreviousErrorKey

The key in an error’s `userInfo` dictionary whose value specifies the previous error when multiple errors occur during transform evaluation.

```
let kSecTransformPreviousErrorKey: CFString
```

## Discussion

Use the value associated with this key to trace through a chain of <doc://com.apple.documentation/documentation/CoreFoundation/CFError> objects when more than one error occurs during transform evaluation.

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