docs: def p_identifier_name_string(self, p):
          """identifier_name_string : identifier_name
          """
          p[0] = asttypes.PropIdentifier(p[1].value)
          # manually clone the position attributes.
          for k in ('_token_map', 'lexpos', 'lineno', 'colno'):
              setattr(p[0], k, getattr(p[1], k))