Open this Url in your browser ->> https://api.login.yahoo.com/oauth/v2/request_auth?oauth_token=nzzuwm5 
 This should be provided to end users of your application.End users should provide their 
'Username' and 'Password' which means they authorize your app. On successful login the end users will see a code in the page 
 This code is the oauth_token which Yahoo returns to your app 
 Enter the code here: