callingAPI.swift

    fileprivate func callKeywordApi() {
        NetworkManager().newGetKeywords { (result) in
            switch result {
            case .success(let keywords):
                self.listOfKeywords = keywords
            case .failure(let error):
                print(error.localizedDescription)
            }
        }
    }

networkCalls.swift

    func newGetKeywords(completion: @escaping (Result<[Keyword], NetworkReponse>) -> Void) {  // Use Result type in our closure parameter
        
        keywordRouter.request(.keywords) { (data, response, error) in
            
            if error != nil {
                print("Check your network connection")
                return
            }
            
            if let response = response as? HTTPURLResponse {
                let result = self.newHandleNetworkResponse(response)
                switch result {
                case .success:
                    guard let responseData = data  else { completion(.failure(.noData)); return }
                    
                    do {
                        let apiResponse = try JSONDecoder().decode([Keyword].self, from: responseData)
                        completion(.success(apiResponse))
                    } catch {
                        completion(.failure(.unableToDecode))
                    }
                case .failure(let networkFailureError):
                    completion(.failure(networkFailureError))
                }
            }
        }
    }