## Modify this and the previous cell to answer Question 4a. Remember to run ##
## the function on the cleaned data files you created from Question 3.      ##

data_file = ('./examples/BayArea-Y3-Summary.csv','./data/Chicago-2016-Summary.csv','./data/NYC-2016-Summary.csv')
for file in data_file:
    print(number_of_trips(file))