---
title: "writeAttributeNullableOctetString(withValue:completion:)"
framework: matter
role: symbol
role_heading: Instance Method
path: "matter/mtrbaseclusterunittesting/writeattributenullableoctetstring(withvalue:completion:)"
---

# writeAttributeNullableOctetString(withValue:completion:)

## Declaration

```swift
func writeAttributeNullableOctetString(withValue value: Data?, completion: @escaping @Sendable ((any Error)?) -> Void)
```

```swift
func writeAttributeNullableOctetString(withValue value: Data?) async throws
```