ios - Call ((Double)->())? in Swift -

i using library rating stars,so i'm trying reference of : public var didfinishtouchingcosmos: ((double)->())?

in view controller got reference of view :

@iboutlet var raitingview: cosmosview! var rating : double?  

then in view controller viewdidload start using way :

raitingview.didfinishtouchingcosmos{rating in         } 

but i'm getting error cannot call value of non-function type((double) ->())?

the library link here : https://github.com/marketplacer/cosmos

you should call function way. basic syntax can check introduction swift apple. recommend read swift tutorial apple through ibook store. free.

raitingview.didfinishtouchingcosmos = { rating in      // want }