Checking Objective-C block type?

This is primarily a curiosity, I'm not really sure what's the practical use of this but here goes.

Since blocks are also Objective-C objects, is it possible to check their type? That is, does it respond to the isKindOfClass: message and how to use that message with respect to blocks?

My naive thought that it's probably like this:

-(void) aMethod {
    typedef int (^BlockA)(int x, int y);
    id blockVar = ...; // get a block from somewhere
    if([blockVar isKindOfClass:BlockA]) {
        BlockA blockVarA = blockVar;
        int result = blockVarA(1,2);
    }
}

The code above probably won't work. But if it is possible to check a block's type, what is the correct way to do it?