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function aa(a, b) {
  function c() {
  }
  c.prototype = b.prototype;
  a.prototype = new c;
  a.prototype.constructor = a;
  for (var d in b) {
    if (Object.defineProperties) {
      var e = Object.getOwnPropertyDescriptor(b, d);
      e && Object.defineProperty(a, d, e);