old_contents: #!/usr/bin/python
  #
  # run-animation.py
  #
  # Usage:
  #     ./run-animation.py
  #
  # Description:
  #     An example to show the iteration animation
  
  import sodtube1d.solver_cese as cese
  import sodtube1d.helper_plot as helper_plot
  import matplotlib.pyplot as plt
  import matplotlib.animation as animation
  
  # initialize the solver
  # initialize the gas status
  solver_cese = cese.Solver()
  solver_cese.init_gas_status()
  solver_cese._data.it_pt_nb = 2
  
  fig = plt.figure()
  ims = []
  # iterate
  for it_nb in range(0, 100):
      solver_cese._data.it_nb = it_nb
      solver_cese.cal_cese_status_before_half_dt()
      solver_cese.cal_cese_status_after_half_dt()
      solver_cese.push_status_along_t()
      # plot the status
      solver_cese.data.refresh_solution()
      solution = list(solver_cese.data.solution)
      ims.append((helper_plot.get_gas_status_plot(solution), ))
  
  im_ani = animation.ArtistAnimation(fig,
                                     ims,
                                     interval=25,
                                     repeat_delay=3000,
                                     blit=True)
  
  plt.show()
  
new_contents: #!/usr/bin/python
  #
  # run-animation.py
  #
  # Usage:
  #     ./run-animation.py
  #
  # Description:
  #     An example to show the iteration animation
  
  import sodtube1d.solver_cese as cese
  import sodtube1d.helper_plot as helper_plot
  import matplotlib.pyplot as plt
  import matplotlib.animation as animation
  
  # initialize the solver
  # initialize the gas status
  solver_cese = cese.Solver()
  solver_cese.init_gas_status()
  solver_cese._data.it_pt_nb = 2
  
  fig = plt.figure()
  frame_seq = []
  # iterate
  for it_nb in range(0, 100):
      solver_cese._data.it_nb = it_nb
      solver_cese.cal_cese_status_before_half_dt()
      solver_cese.cal_cese_status_after_half_dt()
      solver_cese.push_status_along_t()
      # plot the status
      solver_cese.data.refresh_solution()
      solution = list(solver_cese.data.solution)
      # each element of frame_seq should be iterable.
      # the bracket just want to make the artist iterable.
      frame_seq.append((helper_plot.get_gas_status_plot(solution), ))
  
  ani = animation.ArtistAnimation(fig,
                                  frame_seq,
                                  interval=25,
                                  repeat_delay=300,
                                  blit=True)
  
  plt.show()
  
subject: tweak the variable name, repeat_delay and add comments to explain the bracket