Theory: How to connect a method with a block argument? (CDUnknownBlockType)

%hook HTTPClient
- (CDUnknownBlockType)completionForSuccess:(CDUnknownBlockType)arg1 {
}
%end

      

        
        
        
      

    

I'm wondering what to place instead of CDUnknownBlockType

here (generated from dump class). I don’t know the block arguments, so I cannot sign it exactly. Is it possible to instead be used MSHookMessage

with a shared pointer as an argument? Generic pointer void *

didn't work for me here as the post doesn't match.

Is there a way to get the block signature?