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# protocol_conformsToProtocol(_:_:)

Returns a Boolean value that indicates whether one protocol conforms to another protocol.

```
func protocol_conformsToProtocol(_ proto: Protocol?, _ other: Protocol?) -> Bool
```

## Parameters

`proto`

A protocol.

`other`

A protocol.

## Return Value

[`YES`](/documentation/ObjectiveC/YES) if `proto` conforms to `other`, otherwise [`NO`](/documentation/ObjectiveC/NO).

## Discussion

One protocol can incorporate other protocols using the same syntax that classes use to adopt a protocol:

```objc
@protocol ProtocolName < protocol list >
```

All the protocols listed between angle brackets are considered part of the ProtocolName protocol.

---

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