docs: function forEach(hash, iterator, scope) {
      if (!isHash(hash) || typeof iterator !== "function") {
          throw new TypeError();
      }
      var keys = Object.keys(hash), key;
      for (var i = 0, len = keys.length; i < len; ++i) {
          key = keys[i];
          iterator.call(scope || hash, hash[key], key, hash);
      }
      return hash;
  }