yesod - types mismatch on runSqlite and newTVar -


at fpcomplete.com, I was reading a tutorial to use yesod forms. Based on the tutorial, my main task is 

  main = do titems & lt; - Atomically $ newTVar [] liftIO $ warpEnv (link title)   
 What I want to do is start an SQL database in memory, and then put all the data into forms in memory . But even a very simple example does not work:  
  main = runSqlite ": Memory:" $ do - runMigration migrateAll - MichaelId " - $ person insert "Michael" $ 26 - - Michael & Lieutenant; - Michelle Edie - LeftIo $ print Michael Times & lt; - Atomic $ Nutv [] Upper $$ warpEnv (Link Title)   
 I get the error    src / Main.hs@39: 13-39: 36 Expected type 'especlarist t (control.monad.loger.logging t (control.monad trance.resources.microsoft.com) is not in real' io (TOE [a0]) 'in a' do 'block In an STMT: tithem & lt; - atomically $ newTVar [] in the second argument of `($) ', that is,` `{titems & lt; - atomically $ newt [[]; liftIO $ warpEnv (link title)} 'In Expression: Ranslquite': Memory: "$ tax {titems & quot; - atomically $ newTVar []; liftIO $ warpEnv (links title)}   
 I understand that there are some types of mismatch, but to ensure that I have to use which function to solve it. I would greatly appreciate if someone can explain to me what is happening.   
 
 
 You must add  IO  to continuously take action To carry Ond  liftIO   before the nuclear form of

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