@@ -213,11 +213,11 @@
  *	  object.
  *
  * @param object The object which is checked for being in the set
  * @return A boolean whether the set contains the specified object
  */
-- (bool)containsObject: (nullable ObjectType)object;
+- (bool)containsObject: (ObjectType)object;
 
 /*!
  * @brief Returns the value for the specified key
  *
  * If the key starts with an `@`, the `@` is stripped and