Undefined Index : cacheClass,ioClass,authClass

[Sidjain8599]

I'm trying to use google sign in in website.I added all files from src given here but whenever i m trying to run my code , I am getting the following error :

Notice: Undefined index: cacheClass in C:\xampp\htdocs\testing\src\Google_Client.php on line 90

Fatal error: Class name must be a valid object or a string in C:\xampp\htdocs\testing\src\Google_Client.php on line 90

So please solve my problem.

Thanks in advance.