Express addition

node_modules/core-js/modules/_set-species.js

@@ -0,0 +1,13 @@
+'use strict';
+var global = require('./_global');
+var dP = require('./_object-dp');
+var DESCRIPTORS = require('./_descriptors');
+var SPECIES = require('./_wks')('species');
+
+module.exports = function (KEY) {
+  var C = global[KEY];
+  if (DESCRIPTORS && C && !C[SPECIES]) dP.f(C, SPECIES, {
+    configurable: true,
+    get: function () { return this; }
+  });
+};