title: Static variables in protocols
body: <p>I have a protocol A which has a static variabe x. B is a implementation of A. In Class C I pass an instance of B and assigned it to a. How can I access 2 (value of x in class B) from it ? </p>
  
  <pre><code>protocol A {
   static var x : Int { get }  
  }
  
  class B : A {
   static var x: Int {
    return 2 
  }
  }
  
  
  class C {
  // instance of B is assigned to a. 
  let a: A
  
  
  print(a.x)
  }
  </code></pre>