flattenMaps<K2, V2> method
Flattens a map of mutable maps by building a new map from the nested map entries.
If this map contains only instances of Map<K2, V2> the new map will be created correctly, otherwise an exception is thrown.
See flatten.
Implementation
ImmortalMap<K2, V2> flattenMaps<K2, V2>() => ImmortalMap.fromEntries(
cast<K, Map<K2, V2>>().mapEntries((_, map) => map.entries).flatten());