title: haskell [char] to bytestring
body: <pre><code>main :: IO ()
  main = do 
      let a = ("teeeeeeeeeeeeest","teeeeeeeeeeeest")
      b &lt;- app a
      print b
  </code></pre>
  
  <p>app expects (bytestring,bytestring) not ([char],[char])
  how can I convert it?</p>