Course 1 - Part 8 - Lesson 4 - Notebook.ipynb - Added missing imports and variables

[sebasbad]

Hi,

On the Course 1 - Part 8 - Lesson 4 - Notebook.ipynb notebook, I've added a cell with the following code before the Visualizing Intermediate Representations cell

%matplotlib inline

import matplotlib.pyplot as plt

train_horse_names = os.listdir(train_horse_dir)
print(train_horse_names[:10])

train_human_names = os.listdir(train_human_dir)
print(train_human_names[:10])

but the indentation of the notebook source code is different so unfortunately the diff is of no help ...