title: How to tell `keyof MyClass.prototype` in TypeScript?
body: <p>In TypeScript I can define generic and force that in <code>genericForObj</code> passing only properties of a particular object.</p>
  
  <pre class="lang-ts prettyprint-override"><code>class MyClass
  {
    one(){};
    two(){};
  }
  
  function genericForObj&lt;T, K extends keyof T&gt;(obj: T, prop: K)
  {
  
  }
  
  const obj = new MyClass;
  
  genericForObj(obj, 'one'); // OK
  
  genericForObj(MyClass, 'one');
  // Error: Argument of type '"one"' is not
  // assignable to parameter of type '"prototype"'.
  </code></pre>
  
  <p>How to tell <code>keyof MyClass.prototype</code> in generic function?</p>