text: function _classCallCheck(instance, Constructor) {
      if (!(instance instanceof Constructor)) {
          throw new TypeError("Cannot call a class as a function");
      }
  }
  var C = function C(x) {
      "use strict";
      _classCallCheck(this, C);
  };
  var C2 = function C2(x, y) {
      "use strict";
      _classCallCheck(this, C2);
  };
  var a;
  var b;
  