ios - Swift Parse create a user -

i'm new swift, , i'm having difficult time figuring out why code on https://www.parse.com/docs/ios_guide#users/ios isn't working me

var user = pfuser() user.username = "myusername" user.password = "mypassword" user.email = "email@example.com" // other fields can set pfobject user["phone"] = "415-392-0202"  user.signupinbackgroundwithblock { (succeeded: bool!, error: nserror!) -> void in   if error == nil {     // hooray! let them use app now.   } else {     let errorstring = error.userinfo["error"] nsstring     // show errorstring somewhere , let user try again.   } } 

this line

user.signupinbackgroundwithblock  

gives me following error

cannot invoke 'signupinbackgroundwithblock' argument list of type '((bool!, nserror!) -> void)' 

i can copy , paste code objective-c project , works perfectly, when try same swift code. error message. there else need work in swift?

i found solution in case others having similar problem. code below seems working fine. i'm curious know why parse.com gives above code in documentation doesn't work

user.signupinbackgroundwithblock {     (succeeded: bool, error: nserror?) -> void in     if error == nil {         // hooray! let them use app now.     } else {     } }