Hi @praveendvd,
Was checking your public collection. I really found interesting especially google sheets, I was about to try and saw the credentials were already populated. I tried hitting with the same and are not working. I believe it will be better to have those as unset variables in public workspaces. By mistake if we kept the originals, someone may misuse them like I was trying to do so in a way 
The idea to use google sheets is too amazing. I just love that.