Have you actually tried it? Because the people who have (me included) found that both tests will return YES, yet when you try a mutable operation you get an ex

Have you actually tried it? Because the people who have (me included) found that both tests will return YES, yet when you try a mutable operation you get an exception. http://stackoverflow.com/questions/1788690/objective-c-how-to-check-if-variable-is-nsarray-or-nsmutablearray http://stackoverflow.com/questions/1788690/objective-c-how-t... http://www.cocoabuilder.com/archive/cocoa/224795-nsdictionary-mutability-test.html http://www.cocoabuilder.com/archive/cocoa/224795-nsdictionar...