Object key
) Returns true if this map contains the given key
.
Returns true if any of the keys in the map ar equal to key
according to the equality used by the map.
Source
/**
* Returns true if this map contains the given [key].
*
* Returns true if any of the keys in the map ar equal to `key`
* according to the equality used by the map.
*/
bool containsKey(Object key);