Update app.py

app.py

@@ -7,6 +7,7 @@ import numpy as np
 import csv
 from datetime import datetime
 
+import matplotlib.pyplot as plt
 # from matplotlib import pyplot as plt # this lets you draw inline pictures in the notebooks
 # import pylab # this allows you to control figure size 
 # pylab.rcParams['figure.figsize'] = (10.0, 8.0) # this controls figure size in the notebook