title: Ocaml list.map error this function is applied to too many arguments
body: <p>Hello I am new to Ocaml and I am trying to play around with List and list.map. So I write a function helper which takes a list and creates a list of lists.</p>
  
  <pre><code>let rec helper l= 
    match l with 
    | []-&gt;[[]]
    | x::xs -&gt; [x]::helper xs;;
  </code></pre>
  
  <p>Now when i try to use list.map to concatenate to each member of this list of list i get an error.</p>
  
  <p><code>List.map(fun y-&gt;[1]@y) helper [1;2;3];;</code></p>
  
  <p><code>Error: This function is applied to too many arguments;
  maybe you forgot a</code>;'`</p>
  
  <p>I am unable to understand why is this error causes. Any help would be appreciated.</p>
  
  <p>Thank you</p>