old_contents: """Plot the effective area as a function of energy"""
  from pyfoxsi.response import Response
  import matplotlib.pyplot as plt
  
  resp = Response()
  
  resp.plot()
  plt.show()
  
  resp = Response(shutter_state=1)
  
  resp.plot()
  plt.show()
  
new_contents: """Plot the effective area as a function of energy"""
  from pyfoxsi.response import DSIResponse
  import matplotlib.pyplot as plt
  
  resp = DSIResponse()
  
  resp = DSIResponse(shutter_state=0)
  
  resp.plot()
  plt.plot(resp._energies, resp.optic_effective_area, label='Optics only')
  plt.show()
subject: update to example code