title: cannot convert return expression of type 'String' to return type '(Int) -> String'
body: <p>it is normal working  function :</p>
  
  <pre><code>func doSomeThing(productName : String , productPrice : Double)  -&gt; String {
  
          return "good jobs"
      }
  </code></pre>
  
  <p>I might thinking  function can take quantity parameter and return string </p>
  
  <pre><code> func doSomeThing(productName: String , productPrice: Double) -&gt; (Int) -&gt; String{ 
  
       func totaPrice(quantity : Int) -&gt; Double {
  
          return Double(quantity) * productPrice 
  
      }
     return "Product Name \(productName) each price is \(productPrice) , total price \(totaPrice)"
  }
  
  let totaPrice = doSomeThing(productName: "iPhone", productPrice: 649)
  print(totaPrice(5))  
  print(totaPrice(3)) 
  </code></pre>
  
  <p>But below error throwing :</p>
  
  <blockquote>
    <p>ERROR at line 14, col 11: cannot convert return expression of type 'String' to return type '(Int) -> String'
       return "Product Name (productName) each price is (productPrice) , total price (totaPrice)"
              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</p>
  </blockquote>
  
  <p>how can fix this issue ? </p>
  
  <p><strong>Note :I want to  do something like <code>Currying</code> function .</strong></p>