old_contents: //redux-saga
  import { fork } from 'redux-saga/effects'
  
  //sagas
  import * as authentication from './login'
  
  //action
  import * as types from '../constants/actionTypes'
  
  export default function* root() {
      yield [
          fork (authentication.authenticationFlowSaga)
      ]
  }
new_contents: //redux-saga
  import {fork} from 'redux-saga/effects'
  
  //sagas
  import {authenticationFlowSaga} from './login'
  
  export default function* root() {
      yield [
          fork (authenticationFlowSaga)
      ]
  }
subject: remove useless import and fix import