Migration datamodels !

node_modules/es6-weak-map/valid-weak-map.js

@@ -0,0 +1,8 @@
+"use strict";
+
+var isWeakMap = require("./is-weak-map");
+
+module.exports = function (value) {
+	if (!isWeakMap(value)) throw new TypeError(value + " is not a WeakMap");
+	return value;
+};