# cast<RK, RV> method

Map<RK, RV> cast <RK, RV>()

Provides a view of this map as having `RK` keys and `RV` instances, if necessary.

If this map is already a `Map<RK, RV>`, it is returned unchanged.

If this set contains only keys of type `RK` and values of type `RV`, all read operations will work correctly. If any operation exposes a non-`RK` key or non-`RV` value, the operation will throw instead.

Entries added to the map must be valid for both a `Map<K, V>` and a `Map<RK, RV>`.

## Implementation

    Map<RK, RV> cast<RK, RV>() => _map.cast<RK, RV>();