code: def __get_wbfmt_usrfld(self, data_nt):
          
          if self.ntfld_wbfmt is not None:
              if isinstance(self.ntfld_wbfmt, str):
                  ntval = getattr(data_nt, self.ntfld_wbfmt, None) # Ex: 'section'
                  if ntval is not None:
                      return self.fmtname2wbfmtobj.get(ntval, None)
docs: Return format for text cell from namedtuple field specified by 'ntfld_wbfmt