text: 
  const initialState = {
      photos: [],
      isUpdating: false
  };
  
  export function PhotoReducer(state = initialState, action) {
      switch (action.type) {
          case 'PHOTO_FETCHING':
              return {
              ...state,
              isUpdating: true
              };
          case 'PHOTO_RECEIVED':
              return {
                  ...state,
                  isUpdating: false,
                  photos: action.photos
              };
          default:
              return state
      }
    }