code: def _count_elements(mapping, iterable):
      'Tally elements from the iterable.'
      mapping_get = mapping.get
      for elem in iterable:
          mapping[elem] = mapping_get(elem, 0) + f _count_elements(mapping, iterable):
      'Tally elements from the iterable.'
      mapping_get = mapping.get
      for elem in iterable:
          mapping[elem] = mapping_get(elem, 0) + 1
docs: Tally elements from the iterable.