The <*> operator is used to conditionally apply the other parameters to our curried init method. The definition is as follows:

public func <*> <T, U>(f: Decoded<(T) -> U>, x: Decoded<T>) -> Decoded<U> { 
    return x.apply(f) 
} 

func apply<U>(_ f: Decoded<(T) -> U>) -> Decoded<U> { 
    switch (f, self) { 
    case let (.success(function), _): return self.map(function) 
    case let (.failure(le), .failure(re)): return .failure(le + re) 
    case let (.failure(f), _): return .failure(f) 
    } 
}