I am following the instructions in Integrating with OAuth Exercise. When I set the URL property of Common/ExternalURL element, I see an syntax error:

The URL property is as follows:
"https://accounts.google.com/o/oauth2/auth?client_id=" + Site.ClientId +
"&redirect_uri=" +
MakeAbsoluteURL("/Employees_OAuth/GoogleCallback.aspx") + "&scope=" +
EncodeUrl(Site.Scopes) +
"&response_type=code&access_type=offline&approval_prompt=force"

Above property is on page 21 of the instructions. How might I solve this syntax error?