VersionViewModel.swift

// Class definition. You're right, only ONE LINE of code!
class VersionViewModel: BaseViewModel<Version> {}

// Using it
let viewModel = VersionViewModel(provider: MoyaProvider<Service>())
viewModel.fetchData(service: .version(version: AppInfo.version())).startWithResult { result in
  switch result {
  case let .success(version):
    // Handle version success response
  case let .failure(error):
    // Handle error
  }                                                               
}