var WeakMap = WeakMap || (function (s, dP, hOP) {'use strict';
  function WeakMap() { // by Andrea Giammarchi - WTFPL
    dP(this, s, {value: Symbol('WeakMap')});
  }
  WeakMap.prototype = {
    'delete': function del(o) {
      delete o[this[s]];
    },
    get: function get(o) {
      return o[this[s]];
    },
    has: function has(o) {
      return hOP.call(o, this[s]);
    },
    set: function set(o, v) {
      dP(o, this[s], {configurable: true, value: v});
    }
  };
  return WeakMap;
}(Symbol('WeakMap'), Object.defineProperty, {}.hasOwnProperty));