title: Can we declare sealed method in a class
body: <pre><code>class X {
      sealed protected virtual void F() {
          Console.WriteLine("X.F");
      }
      sealed void F1();
      protected virtual void F2() {
          Console.WriteLine("X.F2");
      }
  }
  </code></pre>
  
  <p>In the above code there is compile time error : </p>
  
  <blockquote>
    <p>X.F()' cannot be sealed because it is not an override</p>
    
    <p>X.F1()' cannot be sealed because it is not an override</p>
  </blockquote>
  
  <p>Does it mean we can only apply the <code>sealed</code> keyword whey we have to override some methods?</p>