new_contents: import string
  import matplotlib.pyplot as plt
  import numpy as np
  
  if  __name__=='__main__':
      for line in open('data'):
          dot = line.split()
          plt.plot(dot[0],dot[1],'yo-')
      plt.title("demo")
      plt.ylabel("speed")
      plt.xlabel("time")
      plt.show()
      
subject: add matplot