new_contents: import plotly as py, plotly.graph_objs as go
  from csvparser import parse
  from os.path import basename, splitext
  from sys import argv
  
  data_file = argv[1]
  raw_data = parse(data_file)
  
  sleep_durations = []
  for date, sleeps in raw_data.items():
      total = 0
      for s in sleeps:
          sleep, wake, is_nap = s
          delta_h = round((wake - sleep).seconds / 3600)
          total += delta_h
      sleep_durations.append(total)
  
  min = min(sleep_durations)
  max = max(sleep_durations)
  range = range(min, max + 1)
  hist = [sleep_durations.count(i) for i in range]
  
  data = [go.Bar(x=list(range), y=hist)]
  
  dates = list(raw_data.keys())
  fmt = '%m-%d-%y'
  start = dates[0].strftime(fmt)
  end = dates[-1].strftime(fmt)
  name = splitext(basename(__file__))[0]
  path = '{}_{}--{}.html'.format(name, start, end)
  
  py.offline.plot(data, filename=path)
  
  
subject: Add sleep duration histogram plotter