title: Result of monad inside monad transformer
body: <p>This is my first acquaintance with Monad Transformers, so the answer might be obvious.</p>
  
  <p>Let's say I am inside a do block of type StateT MyMonad MyType, I want to make another function of the same type both modify the state and return a value of type MyMonad MyType. How can I achieve that? I think the examples <a href="http://www.haskell.org/haskellwiki/Simple_StateT_use" rel="noreferrer">here</a> show it in guessSession, yet I can't seem to understand how to apply it!</p>