def get_field_descriptor(self, ref_or_index):
        """
        Parameters
        ----------
        ref_or_index: str or int
            field lowercase name, or field position

        Returns
        -------
        Field descriptor (info contained in Idd)
        """
        if isinstance(ref_or_index, int):
            index = ref_or_index
        else:
            index = self._table._dev_descriptor.get_field_index(ref_or_index)
        return self._table._dev_descriptor.get_field_descriptor(index)
Parameters
        ----------
        ref_or_index: str or int
            field lowercase name, or field position

        Returns
        -------
        Field descriptor (info contained in Idd)