title: Check if NSMutableArray contains a given value
body: <p>I have an <code>NSMutableArray</code> that contains <code>String</code> values. I have a String variable and I want to check if it is contained in the array or not. </p>
  
  <p>I tried using <code>.contains()</code> with String but it say:</p>
  
  <blockquote>
    <p>Cannot convert value of type String to expected argument type...</p>
  </blockquote>
  
  <pre><code>var mutableArray = NSMutableArray()  // ["abc", "123"]
  var string = "abc"
  
  mutableArray.contains("abc") {       // above error in this line
  
  }
  </code></pre>