notContainsKey method
Whether this map does not contain the given key.
Returns false if none of the keys in the map are equal to key
according to the equality used by the map.
final animalRatings = { "aardvark": 1, "baboon": 2 };
final notContainsAardvark = animalRatings.notContainsKey("aardvark"); // false
final notContainsCat = animalRatings.notContainsKey("cat"); // true
Implementation
bool notContainsKey(K key) => !containsKey(key);