code: function(Superclass, constructorFunction) {
      var instance = makeType(constructorFunction);
      instance.prototype = new Superclass();
      instance.prototype.constructor = constructorFunction;
  
      return instance;
    }
docs: subClass
  
  Constructs a structure "subclassed" from a "super class".
  Note: the constructor function passed in should match the
  constructor of the superclass.