code: def format_dateaxis(subplot, freq, index):
      
  
      # handle index specific formatting
      # Note: DatetimeIndex does not use this
      # interface. DatetimeIndex uses matplotlib.date directly
      if isinstance(index, ABCPeriodIndex):
  
          majlocator = TimeSeries_DateLocator(freq, dynamic_mode=True,
                                              minor_locator=False,
                                              plot_obj=subplot)
          minlocator = TimeSeries_DateLocator(freq, dynamic_mode=True,
                                              minor_locator=True,
                                              plot_obj=subplot)
          subplot.xaxis.set_major_locator(majlocator)
          subplot.xaxis.set_minor_locator(minlocator)
  
          majformatter = TimeSeries_DateFormatter(freq, dynamic_mode=True,
                                                  minor_locator=False,
                                                  plot_obj=subplot)
          minformatter = TimeSeries_DateFormatter(freq, dynamic_mode=True,
                                                  minor_locator=True,
                                                  plot_obj=subplot)
          subplot.xaxis.set_major_formatter(majformatter)
          subplot.xaxis.set_minor_formatter(minformatter)
  
          # x and y coord info
          subplot.format_coord = functools.partial(_format_coord, freq)
  
      elif isinstance(index, ABCTimedeltaIndex):
          subplot.xaxis.set_major_formatter(
              TimeSeries_TimedeltaFormatter())
      else:
          raise TypeError('index type not supported')
  
      pylab.draw_if_interactive()
docs: Pretty-formats the date axis (x-axis).
  
      Major and minor ticks are automatically set for the frequency of the
      current underlying series.  As the dynamic mode is activated by
      default, changing the limits of the x axis will intelligently change
      the positions of the ticks.