code: def archive_observer(population, num_generations, num_evaluations, args):
      
      archive = args['_ec'].archive
      print('----------------------------------------------------------------------------')
      print('                         Archive ({0:5} individuals)'.format(len(archive)))
      print('----------------------------------------------------------------------------')
      for a in archive:
          print(a)
      print('----------------------------------------------------------------------------')
docs: Print the current archive to the screen.
      
      This function displays the current archive of the evolutionary 
      computation to the screen. 
      
      .. Arguments:
         population -- the population of Individuals
         num_generations -- the number of elapsed generations
         num_evaluations -- the number of candidate solution evaluations
         args -- a dictionary of keyword arguments