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# subscript(dynamicMember:)

Access the value of the attribute to constrain.

```
subscript(dynamicMember keyPath: KeyPath<AttributeDynamicLookup, Attribute>) -> Attribute.Value? { get set }
```

## Overview

For details on how attribute value constraining works, refer to
[`constrain(_:)`](/documentation/SwiftUI/AttributedTextValueConstraint/constrain(_:)).

---

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