title: 2 classes implement same interface, duplicated code
body: <p>I have an interface:</p>
  
  <pre><code>public interface IUser
  {
  
  }
  </code></pre>
  
  <p>And then 2 classes that implement this interface:</p>
  
  <pre><code>public class User : IUser 
  {
  
  }
  
  public class AdminUser : IUser
  {
  
  }
  </code></pre>
  
  <p>Now the problem I see is that there is duplicate code between User and AdminUser when implementing a method in the interface.</p>
  
  <p>Can I introduce an abstract class that would implement the common code between User and AdminUser somehow?</p>
  
  <p>I don't want AdminUser to inherit from User.</p>