old_contents: data = []
  
  def plot(x, y, label=None):
      d = {
          "data": zip(x, y),
          }
      if label:
          d["label"] = label
      data.append(d)
  
  def show():
      from plotserver.runserver import main
      main()
  
  def grid(*args, **kwargs):
      pass
  
  def legend(*args, **kwargs):
      pass
  
new_contents: data = []
  
  def plot(x, y, format=None, label=None, lw=None):
      d = {
          "data": zip(x, y),
          }
      if label:
          d["label"] = label
      data.append(d)
  
  def show():
      from plotserver.runserver import main
      main()
  
  def grid(*args, **kwargs):
      pass
  
  def legend(*args, **kwargs):
      pass
  
subject: Add format and lw kwargs