OCMock method name collision

i'm a new user of OCMock, so maybe i'm just missing something simple here. this code does not compile: ``` id mockSession = [OCMockObject mockForClass:[AVCaptureSession class]]; [[mockSession expect] addOutput:[OCMArg anyPointer]]; ``` the error is ``` Multiple methods named 'addOutput:' found with mismatched result, parameter type or attributes ``` the signature of the method addOutput on AVCaptureSession is as follows ``` - (void)addOutput:(AVCaptureOutput *)output ``` as far as i can tell, the problem is that the method addOutput exists on both the AVCaptureSession and AVAssetReader classes. the method signature for addOutput on AVAssetReader is as follows. ``` - (void)addOutput:(AVAssetReaderOutput *)output ``` apparently the compiler thinks my mockSession is an AVAssetReader, but i don't know why it chooses that class instead of AVCaptureSession. if i expect a different method on AVCaptureSession that does not exist on AVAssetReader, then it compiles. i have tried the following without success. it compiles, but crashes. ``` id mockSession = [OCMockObject mockForClass:[AVCaptureSession class]]; [(AVCaptureSession*)[mockSession expect] addOutput:[OCMArg anyPointer]]; ``` this code also does not compile, with the same error as the previous one ``` id mockSession = [OCMockObject mockForClass:[AVCaptureSession class]]; AVCaptureVideoDataOutput *output = [[AVCaptureVideoDataOutput alloc] init]; [[mockSession expect] addOutput:output]; ``` any guidance here?