Code Sign error: Certificate identity

This is a silly iPhone apps certificate error that gets into my nerve.

But the fix is really simple.

When you compile your iphone / ipad apps, and you get the following errors:
"Code Sign error: Certificate identity 'iPhone Developer"

All you need to do is to :

1. Open the Keychain application at "Utilities->KeyChain Access"
2. When you compile your application, you'll see sometimes there are multiple Certificates are being added. Keep the keychain and xcode open. Delete the duplicate certificates.
3. Recompile
4. If you see code sign error, it just means that you have to download the certificate again. Go to the 
https://developer.apple.com/, and retrieve the certificate. Double click on it, and it should be added.
5. Recompile.

Done!!!