code: def _normalize_and_accrue_digits_and_plus_sign(self, next_char, remember_position):
          
          if next_char == _PLUS_SIGN:
              normalized_char = next_char
              self._accrued_input_without_formatting += next_char
          else:
              next_digit = unicode_digit(next_char, -1)
              if next_digit != -1:
                  normalized_char = unicod(next_digit)
              else:  # pragma no cover
                  normalized_char = next_char
              self._accrued_input_without_formatting += normalized_char
              self._national_number += normalized_char
          if remember_position:
              self._position_to_remember = len(self._accrued_input_without_formatting)
          return normalized_char
docs: Accrues digits and the plus sign to
          _accrued_input_without_formatting for later use. If next_char contains
          a digit in non-ASCII format (e.g. the full-width version of digits),
          it is first normalized to the ASCII version. The return value is
          next_char itself, or its normalized version, if next_char is a digit
          in non-ASCII format. This method assumes its input is either a digit
          or the plus sign.