title: Certain Instance Method Cannot be Found Under DispatchQueue
body: <pre><code>func calculator (yourName : String, theirName : String) -&gt; String {
  
  
  let score = 90
  
  if score &gt; 80 {
      return "Higher than 80%"
  }
  
  else {
      return "Lower than 80%"
  }
  
  return score    //Error 
  }
  </code></pre>
  
  <p>Because score is not a string I get this error: </p>
  
  <pre><code>Cannot convert return expression of type 'Int' to return type 'String'
  </code></pre>
  
  <p>I have seen solutions which call for the returning of values to all be in one line. However, it wouldn't work in this case because only one value needs to be returned... </p>
  
  <p>How would I fix this problem?</p>