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# init(merge:)

Returns a merge policy initialized with a given policy type.

```
init(merge ty: NSMergePolicyType)
```

## Parameters

`ty`

A merge policy type.

## Return Value

A merge policy initialized with a given policy type.

## Discussion

If you override this method in a subclass, you should invoke the superclass’s implementation with the merge policy that is closest to the behavior you want.

- This will make it easier to use the superclass’s implementation of [`resolve(mergeConflicts:)`](/documentation/CoreData/NSMergePolicy/resolve(mergeConflicts:)) and then customize the results.
- Due to the complexity of merging to-many relationships, this class is designed with the expectation that you call super as the base implementation.

## See Also

  [Core Data Model Versioning and Data Migration Programming Guide](https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/CoreDataVersioning/Articles/Introduction.html#//apple_ref/doc/uid/TP40004399)


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