Image directories incorrectly specified? (Deep Learning - exercise 4) about learntools HOT 3 CLOSED

Found 220 images belonging to 2 classes.
Found 217 images belonging to 2 classes.
 3/22 [===>..........................] - ETA: 1s - loss: 0.2108 - acc: 0.9667
/opt/conda/lib/python3.6/site-packages/keras_preprocessing/image/image_data_generator.py:699: UserWarning: This ImageDataGenerator specifies `featurewise_center`, but it hasn't been fit on any training data. Fit it first by calling `.fit(numpy_data)`.
  warnings.warn('This ImageDataGenerator specifies '
7/7 [==============================] - 1s 129ms/step - loss: 0.1463 - acc: 0.9493
22/22 [==============================] - 2s 90ms/step - loss: 0.1554 - acc: 0.9455 - val_loss: 0.1463 - val_acc: 0.9493
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-10-17ece9deb558> in <module>()
     23                                        validation_steps=1)
     24 
---> 25 step_4.check()

/opt/conda/lib/python3.6/site-packages/learntools/core/problem_view.py in wrapped(self, *args, **kwargs)
     22     def wrapped(self, *args, **kwargs):
     23         self.interactions[method.__name__] += 1
---> 24         return method(self, *args, **kwargs)
     25     return wrapped
     26 

/opt/conda/lib/python3.6/site-packages/learntools/core/problem_view.py in wrapped(*args, **kwargs)
     13     @functools.wraps(fn)
     14     def wrapped(*args, **kwargs):
---> 15         res = fn(*args, **kwargs)
     16         display(res)
     17         # Don't propagate the return to avoid double printing.

/opt/conda/lib/python3.6/site-packages/learntools/core/problem_view.py in check(self)
     81                 args = ()
     82             self.problem.check_whether_attempted(*args)
---> 83             self.problem.check(*args)
     84         except NotAttempted as e:
     85             self._track_check(tracking.OutcomeType.UNATTEMPTED)

/opt/conda/lib/python3.6/site-packages/learntools/deep_learning/exercise_4.py in check(self, fit_stats)
     55     _hint = "To get steps_per_epoch, divide the number of images by the batch size."
     56     def check(self, fit_stats):
---> 57         their_val_dir = fit_stats.validation_data.directory
     58         their_val_loss = fit_stats.history['val_loss'][0]
     59         their_num_steps = fit_stats.params['steps']

AttributeError: 'NoneType' object has no attribute 'directory'