throw new Error('Please Set a Template Directory');

I got this error, even the path directory to templates is correct
this is My Code :100:
```
var sendemail = require('sendemail');
var path = require('path');
var dir ='./templates'; // unresolved

sendemail.set_template_directory(dir);
var options = {
templateName: 'welcome',
context: {
tempalateVariableName: 'Variable Value',
name: 'Joe Bloggs'
},
subject: 'Welcome to Email',
senderEmailAddress: 'me@gmail.com',
toAddresses: ['me@gmail.com', 'me@gmail.com'],

htmlCharset: 'utf16',
textCharset: 'utf16',
subjectCharset: 'utf8'
};

sendemail.sendMany(options, callback);
```