docs: function () {
  
          var Proto = $prototype (),  // empty argument read as {}
              dummy = function () {}
  
          $assert ($prototype.isConstructor (Proto), true)
          $assert ($prototype.isConstructor (dummy), false)
          $assert ($prototype.isConstructor (null),  false) // regression
  
          $assert ([Proto, dummy].map ($prototype.isConstructor), [true, false]) }