code: def raster(times, indices, max_time=None, max_index=None, 
             x_label="Timestep", y_label="Index", **kwargs):
      
      # set default size to 1
      if 's' not in kwargs:
          kwargs['s'] = 1
      scatter(times, indices, **kwargs)
      
      if max_time is None:
          max_time = max(times)
      if max_index is None:
          max_index = max(indices)
      axis((0, max_time, 0, max_index))
      if x_label is not None: xlabel(x_label)
      if y_label is not None: ylabel(y_label)
docs: Plots a raster plot given times and indices of events.