var animation = [String: Void]()
animation["a"] = animationA()

//Así lo declaro
var array: [(Void -> Void)] = []
//Aquí asigno la función
array.append { () -> () in
            self.animationDefault()
        }
//Así ejecuto la función
array[0]()

var animation: [String: () -> ()] = [
    "a":
    {() -> () in self.animationA()}
]
animation["a"]!()