code: def normalize(self, form):
          
          import unicodedata
          f = lambda x: unicodedata.normalize(form, x)
          result = _na_map(f, self._parent)
          return self._wrap_result(result)
docs: Return the Unicode normal form for the strings in the Series/Index.
          For more information on the forms, see the
          :func:`unicodedata.normalize`.
  
          Parameters
          ----------
          form : {'NFC', 'NFKC', 'NFD', 'NFKD'}
              Unicode form
  
          Returns
          -------
          normalized : Series/Index of objects