The contains() method of Scala is equivalent to the isDefinedAt method of Scala but the only difference is that isDefinedAt is observed on all the PartialFunction classes while contains is clearly defined to the Map interface of Scala. It checks whether the stated map contains a binding for a key or not.
def contains(key: K): Boolean
Where, k is the key.
It returns true if there is a binding for the key in the map stated else returns false.
Here, contains method has a key identical to the key present in the map stated above so, it returns true.
Here, contains method has a key which is not identical to the key present in the map stated above so, it returns false.