diff --git a/lib/models/email.js b/lib/models/email.js
index e9358b2b..9bb3a79c 100644
--- a/lib/models/email.js
+++ b/lib/models/email.js
@@ -4,7 +4,8 @@
 
 var Model = require('../loopback').Model
   , loopback = require('../loopback')
-  , mailer = require("nodemailer"); 
+  , mailer = require('nodemailer')
+  , assert = require('assert');
 
 /**
  * Default Email properties.
@@ -106,4 +107,4 @@ Email.prototype.mailer = mailer;
 
 Email.prototype.send = function (fn) {
   this.constructor.send(this, fn);
-}
\ No newline at end of file
+}