title: how to istantiate and use std::less specialization object
body: <p>this is from a test.
  the task: make a generic function object that behaves exactly like std::less with the exception that it always return true.
  and the given solution:</p>
  
  <pre><code>template&lt;class T&gt;
  struct myless : less&lt;T&gt; {
      bool operator(T, T) const { return true; }
  };
  </code></pre>
  
  <p>How to instantiate and use it?</p>